ANSYS CFX Introduction

ANSYS CFX Introduction

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ANSYS CFX Introduction

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Table of Contents1. Computational Fluid Dynamics ........................................................................................................... 5

The History of CFD ............................................................................................................. 5The Mathematics of CFD ...................................................................................................... 5Uses of CFD ....................................................................................................................... 6CFD Methodology ............................................................................................................... 6Creating the Geometry/Mesh ................................................................................................. 8Defining the Physics of the Model .......................................................................................... 8Solving the CFD Problem ..................................................................................................... 8Visualizing the Results in the Post-processor ............................................................................. 9Further Background Reading ................................................................................................. 9

2. Overview of ANSYS CFX ................................................................................................................ 11The Structure of ANSYS CFX .............................................................................................. 11CFX-Pre .......................................................................................................................... 12CFX-Solver ...................................................................................................................... 12CFX-Solver Manager .......................................................................................................... 13CFD-Post ......................................................................................................................... 13Getting Started with ANSYS CFX ......................................................................................... 13Running ANSYS CFX ........................................................................................................ 13CFX Help, Tutorials, and Reference Information ...................................................................... 14The Directory Structure of ANSYS CFX ................................................................................ 14CFX File Types ................................................................................................................. 15Starting ANSYS CFX Components from the Command Line ..................................................... 16Obtaining System Information with the cfx5info Command ....................................................... 16

3. What's New in CFX ........................................................................................................................ 19New Meshing Application and Automatic Virtual Topology ........................................................ 19Automatic Virtual Topology ................................................................................................. 19Physical Models and Solver Improvements ............................................................................. 19CFX Compiler in Windows .................................................................................................. 19ANSYS FSI Coupling ......................................................................................................... 20Moving Mesh Extensions .................................................................................................... 20Problem Size and Efficiency Improvements ............................................................................ 20Expression Language Advances ............................................................................................ 20Particle Tracking Extensions ................................................................................................ 20Turbulence Modeling .......................................................................................................... 21Combustion and Radiation Improvements ............................................................................... 21Domain Interfaces .............................................................................................................. 22Boundary Conditions and Boundary Sources ........................................................................... 22Eulerian Multiphase Extensions ............................................................................................ 22CFX-Pre .......................................................................................................................... 22Default Domain and Interface Generation ............................................................................... 23CFD-Post ......................................................................................................................... 23Beta Features .................................................................................................................... 24Supported Platforms ........................................................................................................... 24

4. Customizing ANSYS CFX ............................................................................................................... 25ANSYS CFX Resource Configuration Files ............................................................................ 25The Site-wide Configuration Files ......................................................................................... 25User's Configuration Files ................................................................................................... 25Syntax of CFX Resource Configuration Files .......................................................................... 26Resources Set in cfx5rc Files ................................................................................................ 26

5. Using the CFX Launcher .................................................................................................................. 29Starting the CFX Launcher .................................................................................................. 29

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6. ANSYS CFX in ANSYS Workbench .................................................................................................. 31The ANSYS Workbench Interface ......................................................................................... 31Toolbox ........................................................................................................................... 32Project Schematic .............................................................................................................. 33View Bar .......................................................................................................................... 34Properties View ................................................................................................................. 34Files View ........................................................................................................................ 35Sidebar Help ..................................................................................................................... 36Shortcuts (Context Menu Options) ........................................................................................ 36An Introduction to Workflow within ANSYS CFX in ANSYS Workbench .................................... 36Data Flow in Systems and Between Systems ........................................................................... 39Known Limitations of Using ANSYS CFX in ANSYS Workbench .............................................. 39

7. Help On Help ................................................................................................................................ 41CFX Documentation Structure .............................................................................................. 41Document Conventions ....................................................................................................... 42Spelling Conventions .......................................................................................................... 42File and Directory Names .................................................................................................... 43User Input ........................................................................................................................ 43Input Substitution ............................................................................................................... 43Optional Arguments ........................................................................................................... 43Long Commands ............................................................................................................... 43Operating System Names .................................................................................................... 43Accessing Online Help ........................................................................................................ 44If CHM Files Cannot be Accessed Over a Network ................................................................... 44Adjusting Font Sizes in Online Help ...................................................................................... 44Using the Help Browser Index .............................................................................................. 44Using the Search Feature ..................................................................................................... 45Bookmarking Useful Help Pages ........................................................................................... 45

8. Contact Information ........................................................................................................................ 47How to Contact ANSYS Customer Service ............................................................................. 47ANSYS Customer Portal ..................................................................................................... 47

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Chapter 1. Computational FluidDynamicsComputational Fluid Dynamics (CFD) is a computer-based tool for simulating the behavior of systems involving fluidflow, heat transfer, and other related physical processes. It works by solving the equations of fluid flow (in a specialform) over a region of interest, with specified (known) conditions on the boundary of that region.

This chapter discusses:

• The History of CFD (p. 5)

• The Mathematics of CFD (p. 5)

• Uses of CFD (p. 6)

• CFD Methodology (p. 6)

• Further Background Reading (p. 9)

The History of CFDComputers have been used to solve fluid flow problems for many years. Numerous programs have been written tosolve either specific problems, or specific classes of problems. From the mid-1970's, the complex mathematics requiredto generalize the algorithms began to be understood, and general purpose CFD solvers were developed. These beganto appear in the early 1980's and required what were then very powerful computers, as well as an in-depth knowledgeof fluid dynamics, and large amounts of time to set up simulations. Consequently, CFD was a tool used almost exclusivelyin research.

Recent advances in computing power, together with powerful graphics and interactive 3D manipulation of models,have made the process of creating a CFD model and analyzing results much less labor intensive, reducing time and,hence, cost. Advanced solvers contain algorithms which enable robust solutions of the flow field in a reasonable time.

As a result of these factors, Computational Fluid Dynamics is now an established industrial design tool, helping toreduce design time scales and improve processes throughout the engineering world. CFD provides a cost-effective andaccurate alternative to scale model testing, with variations on the simulation being performed quickly, offering obviousadvantages.

The Mathematics of CFDThe set of equations which describe the processes of momentum, heat and mass transfer are known as the Navier-Stokesequations. These partial differential equations were derived in the early nineteenth century and have no known generalanalytical solution but can be discretized and solved numerically.

Equations describing other processes, such as combustion, can also be solved in conjunction with the Navier-Stokesequations. Often, an approximating model is used to derive these additional equations, turbulence models being aparticularly important example.

There are a number of different solution methods which are used in CFD codes. The most common, and the one onwhich CFX is based, is known as the finite volume technique.

In this technique, the region of interest is divided into small sub-regions, called control volumes. The equations arediscretized and solved iteratively for each control volume. As a result, an approximation of the value of each variableat specific points throughout the domain can be obtained. In this way, one derives a full picture of the behavior of theflow.

Additional information on the Navier-Stokes equations and other mathematical aspects of the CFX software suite isavailable. For details, see Basic Solver Capability Theory (p. 13) in the ANSYS CFX-Solver Theory Guide.

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Uses of CFDCFD is used by engineers and scientists in a wide range of fields. Typical applications include:

• Process industry: Mixing vessels, chemical reactors

• Building services: Ventilation of buildings, such as atriums

• Health and safety: Investigating the effects of fire and smoke

• Motor industry: Combustion modeling, car aerodynamics

• Electronics: Heat transfer within and around circuit boards

• Environmental: Dispersion of pollutants in air or water

• Power and energy: Optimization of combustion processes

• Medical: Blood flow through grafted blood vessels

CFD MethodologyCFD can be used to determine the performance of a component at the design stage, or it can be used to analyze difficultieswith an existing component and lead to its improved design.

For example, the pressure drop through a component may be considered excessive:

The first step is to identify the region of interest:

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The geometry of the region of interest is then defined. If the geometry already exists in CAD, it can be imported directly.The mesh is then created. After importing the mesh into the pre-processor, other elements of the simulation includingthe boundary conditions (inlets, outlets, etc.) and fluid properties are defined.

The flow solver is run to produce a file of results that contains the variation of velocity, pressure and any other variablesthroughout the region of interest.

The results can be visualized and can provide the engineer an understanding of the behavior of the fluid throughoutthe region of interest.


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This can lead to design modifications which can be tested by changing the geometry of the CFD model and seeing theeffect.

The process of performing a single CFD simulation is split into four components:

1. Creating the Geometry/Mesh (p. 8)

2. Defining the Physics of the Model (p. 8)

3. Solving the CFD Problem (p. 8)

4. Visualizing the Results in the Post-processor (p. 9)

Creating the Geometry/MeshThis interactive process is the first pre-processing stage. The objective is to produce a mesh for input to the physicspre-processor. Before a mesh can be produced, a closed geometric solid is required. The geometry and mesh can becreated in ANSYS Meshing or any of the other geometry/mesh creation tools. The basic steps involve:

1. Defining the geometry of the region of interest.

2. Creating regions of fluid flow, solid regions and surface boundary names.

3. Setting properties for the mesh.

This pre-processing stage is now highly automated. In CFX, geometry can be imported from most major CAD packagesusing native format, and the mesh of control volumes is generated automatically.

Defining the Physics of the ModelThis interactive process is the second pre-processing stage and is used to create input required by the Solver. The meshfiles are loaded into the physics pre-processor, CFX-Pre.

The physical models that are to be included in the simulation are selected. Fluid properties and boundary conditionsare specified.

Solving the CFD ProblemThe component that solves the CFD problem is called the Solver. It produces the required results in anon-interactive/batch process. A CFD problem is solved as follows:


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1. The partial differential equations are integrated over all the control volumes in the region of interest. This isequivalent to applying a basic conservation law (for example, for mass or momentum) to each control volume.

2. These integral equations are converted to a system of algebraic equations by generating a set of approximationsfor the terms in the integral equations.

3. The algebraic equations are solved iteratively.

An iterative approach is required because of the non-linear nature of the equations, and as the solution approaches theexact solution, it is said to converge. For each iteration, an error, or residual, is reported as a measure of the overallconservation of the flow properties.

How close the final solution is to the exact solution depends on a number of factors, including the size and shape ofthe control volumes and the size of the final residuals. Complex physical processes, such as combustion and turbulence,are often modeled using empirical relationships. The approximations inherent in these models also contribute todifferences between the CFD solution and the real flow.

The solution process requires no user interaction and is, therefore, usually carried out as a batch process.

The solver produces a results file which is then passed to the post-processor.

Visualizing the Results in the Post-processorThe post-processor is the component used to analyze, visualize and present the results interactively. Post-processingincludes anything from obtaining point values to complex animated sequences.

Examples of some important features of post-processors are:

• Visualization of the geometry and control volumes

• Vector plots showing the direction and magnitude of the flow

• Visualization of the variation of scalar variables (variables which have only magnitude, not direction, such astemperature, pressure and speed) through the domain

• Quantitative numerical calculations

• Animation

• Charts showing graphical plots of variables

• Hardcopy and online output.

Further Background ReadingThe following is a selection of books related to fluids, thermodynamics, CFD and computing:

• An Introduction to Computational Fluid Dynamics, The Finite Volume Method

H K Versteeg and W Malalasekera; Longman, 1995. An excellent introduction to the theory of CFD withwell-presented derivations of the equations.

• Using Computational Fluid Dynamics

C T Shaw; Prentice Hall, 1992. An introduction to the practical aspects of using CFD.

• Numerical Heat Transfer and Fluid Flow

S V Patankar; Taylor & Francis, 1980. A standard text on the details of numerical methods.

• Engineering Thermodynamics: Work and Heat Transfer

G F C Rogers and Y R Mayhew; Longman, 1996. An undergraduate thermodynamics text book.

• Mechanics of Fluids

Bernard Massey, Spon Press, 1998. An undergraduate fluid mechanics text book.


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• Viscous Fluid Flow

F M White; McGraw Hill, 2005. An advanced text on fluid dynamics.

• Perry's Chemical Engineer's Handbook (7th Edition)

McGraw Hill Professional Publishing, 1997. A superb reference for the physical properties of fluids.

• An Album of Fluid Motion

Milton Van Dyke, The Parabolic Press, 1982. Fluid flow phenomena demonstrated in pictures.

If you are unfamiliar with using the UNIX operating system or with UNIX system administration, you may like toobtain and read the following books:

• UNIX in a Nutshell, Fourth Edition

Daniel Gilly and the staff of O'Reilly & Associates, Inc, O'Reilly & Associates, Inc, 2005. An excellent UNIXreference book.

• Learning the UNIX Operating System

Grace Todino-Gonguet, John Strang, and Jerry Peek; O'Reilly & Associates, Inc, 2002.

• Essential System Administration

Æleen Frisch; O'Reilly & Associates, Inc, 2002.

• A Scientist's and Engineer's Guide to Workstations and Supercomputers

Rubin H Landau and Paul J Fink Jr., John Wiley and Sons Inc., 1993. A clear and practical guide to powerfulcomputers that use the UNIX operating system.


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Chapter 2. Overview of ANSYS CFXANSYS CFX is a general purpose Computational Fluid Dynamics (CFD) software suite that combines an advancedsolver with powerful pre- and post-processing capabilities. It includes the following features:

• An advanced coupled solver that is both reliable and robust.

• Full integration of problem definition, analysis, and results presentation.

• An intuitive and interactive setup process, using menus and advanced graphics.

CFX is capable of modeling:

• Steady-state and transient flows

• Laminar and turbulent flows

• Subsonic, transonic and supersonic flows

• Heat transfer and thermal radiation

• Buoyancy

• Non-Newtonian flows

• Transport of non-reacting scalar components

• Multiphase flows

• Combustion

• Flows in multiple frames of reference

• Particle tracking.


• The Structure of ANSYS CFX (p. 11)

• CFX-Pre (p. 12)

• CFX-Solver (p. 12)

• CFX-Solver Manager (p. 13)

• CFD-Post (p. 13)

• Getting Started with ANSYS CFX (p. 13)

• The Directory Structure of ANSYS CFX (p. 14)

• CFX File Types (p. 15)

• Starting ANSYS CFX Components from the Command Line (p. 16)

The Structure of ANSYS CFXANSYS CFX consists of four software modules that take a geometry and mesh and pass the information required toperform a CFD analysis:


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CFX File Types (p. 15) show the file types involved in this data flow.

CFX-PreThe next-generation physics pre-processor, CFX-Pre, is used to define simulations.

Multiple meshes may be imported, allowing each section of complex geometries to use the most appropriate mesh.

Analyses, which consist of flow physics, boundary conditions, initial values and solver parameters are also specified.A full range of boundary conditions, including inlets, outlets and openings, together with boundary conditions for heattransfer models and periodicity, are all available in ANSYS CFX through CFX-Pre; for details, see CFX-Pre Basics(p. 15).

Complex simulations are assembled from one or more configurations, each of which combines an analysis definitionwith other related tasks such as remeshing. Control over the configuration execution order and inter-configurationsolution dependencies then facilitates the setup of relatively common simulations like those involving the initializationof a transient analysis using results from a steady state analysis. Use of multiple configurations and control alsofacilitates the setup of increasingly complex simulations of, for example, performance curves for turbo-machines orinternal combustion engines with evolving geometry and physics.

CFX-SolverCFX-Solver solves all the solution variables for the simulation for the problem specification generated in CFX-Pre.

One of the most important features of ANSYS CFX is its use of a coupled solver, in which all the hydrodynamicequations are solved as a single system. The coupled solver is faster than the traditional segregated solver and feweriterations are required to obtain a converged flow solution.


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Additional information on the CFX-Solver models is available; for details, see Basic Capabilities Modeling (p. 19) inthe ANSYS CFX-Solver Modeling Guide.

CFX-Solver ManagerThe CFX-Solver Manager module provides greater control to the management of the CFD task. Its major functionsare:

• Specify the input files to the CFX-Solver.

• Start/stop the CFX-Solver.

• Monitor the progress of the solution.

• Set up the CFX-Solver for a parallel calculation.

Additional information on the CFX-Solver Manager is available; for details, see CFX-Solver Manager Basics (p. 9)in the ANSYS CFX-Solver Manager User's Guide.

CFD-PostCFD-Post provides state-of-the-art interactive post-processing graphics tools to analyze and present the CFX simulationresults.

Important features include:

• Quantitative post-processing

• Report generation (see Report (p. 41)).

• Command line, session file, or state file input (see File Types Used and Produced by CFD-Post (p. 93)).

• User-defined variables

• Generation of a variety of graphical objects where visibility, transparency, color, and line/face rendering can becontrolled (see CFD-Post Insert Menu (p. 111) in the ANSYS CFD-Post User's Guide).

• Power Syntax to allow fully programmable session files (see Power Syntax in ANSYS CFX (p. 287) in the ANSYSCFX Reference Guide).

Additional information on CFD-Post is available; for details, see Overview of CFD-Post (p. 15) in the ANSYS CFD-PostUser's Guide.

Getting Started with ANSYS CFXThis section helps you learn the basics of using ANSYS CFX, such as running ANSYS CFX, accessing tutorials, andusing the context-sensitive online help. It assumes that you have installed the ANSYS software, a process that isdescribed in the installation documentation.

The following topics will be discussed:

• Running ANSYS CFX (p. 13)

• CFX Help, Tutorials, and Reference Information (p. 14)

Running ANSYS CFX

Do this:To run ANSYS CFX on this operating system:

Enter cfx5 in a terminal window.UNIX

Select Start > All Programs > ANSYS 12.0 > CFX > ANSYSCFX 12.0

Windows


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This opens the CFX Launcher, from which all other components of ANSYS CFX can be accessed. You will usuallywant to start by setting your Working Directory (where all files will be written to) and then opening CFX-Pre byclicking the CFX-Pre button.

NoteYou can also start ANSYS components from the command line. See Starting ANSYS CFX Componentsfrom the Command Line (p. 16).

CFX Help,Tutorials, and Reference InformationAccess to the CFX online help system is available through a number of routes:

• To view tutorials, user guides, and reference manuals in online-help form, select Help from the ANSYS product'smenu bar.

• To view context-sensitive help on an item of interest, press the F1 key (or on Sun workstations, the Help key) whenthe focus is on that item.

• The CFX documentation is also provided in PDF format. To view the tutorials, user guides, and reference manualsin PDF format, go to <CFXROOT>..\commonfiles\help\en-us\CFX\help\pdf\ on Windows or<CFXROOT>../commonfiles/help/en-us/CFX/help/pdf/ on UNIX. On Windows you can alsoaccess PDF files from the menu bar by selecting Help > PDF.

You will need a PDF viewer such as Adobe Reader (available from http://www.adobe.com) to view or print thesePDF files.

For more information, see CFX Documentation Structure (p. 41).

The Directory Structure of ANSYS CFXThe directory in which ANSYS CFX is installed is referred to as <CFXROOT>. This directory contains all the filesyou will need to run ANSYS CFX. <CFXROOT> is release-specific to enable you to run more than one release ofANSYS CFX. The release-specific directory often contains directories for each operating system on which you maywant to run the CFX software. These will contain the system-dependent binary executable files needed by CFX.

Some of the important directories immediately under <CFXROOT> are:

The bin directory contains all the commands that are normally run directly by users. It containsmostly “wrapper” scripts that call the appropriate script for the release you are running in therelease-specific subdirectory, for example, CFX.

bin

The config directory contains the host definition file for CFX software.config

The etc directory contains various data files common to all supported system types.etc

The examples directory contains files that will help you work through the CFX tutorials. Thereare some sample meshes, CAD files, session files, CFX expression language files, User Fortranexamples, and example C source code files.

examples

The help directory contains the CFX documentation in online (.jar and .chm) and printable(.pdf) formats.

help

The include directory contains header files used by parts of the CFX software.include

If it is present, the lib directory contains various libraries needed to relink the CFX-Solver oruser-defined mesh import or mesh export.

lib

Contains software tools such as cygwin, mpi, mpich, perl, pvm (UNIX only), and qt.tools


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CFX File TypesDuring the process of creating the model, running the CFX-Solver and analyzing the results, a number of differentfiles are created by the various modules of the software. This section describes some of these files and their purposes.

The use of these files with their default extension is shown in the following flowchart. The standard files used andproduced are indicated with solid black lines; other possible uses are indicated with dotted lines.

Details of the main file types can be found in:

• CFX-Pre File Types (p. 26)

• CFX-Solver Files (p. 33)

• File Types Used and Produced by CFD-Post (p. 93)

• Supported Mesh File Types (p. 66) in the ANSYS CFX-Pre User's Guide

For information on producing files for input into other post-processors, see File Export Utility (p. 143) in the ANSYSCFX-Solver Manager User's Guide.


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Starting ANSYS CFX Components from theCommand LineThe components of CFX can all be started from the command line, as well as from within other modules of CFX.Additional information on command lines in Windows is available; for details, see Command Line (p. 15). A typicalcommand consists of the command name, followed by various arguments, many of which are optional.

For example, to start up CFX-Pre and play the session file, open a terminal window and enter the command:

cfx5pre -play StaticMixer.pre

The following table lists some of the commands you can use to start up CFX components.

ArgumentsCommandComponent

See Starting the CFX Launcher (p. 29).cfx5CFX Launcher

or

cfx5launch

See Starting CFX-Pre from the Command Line (p. 15) in theANSYS CFX-Pre User's Guide.

cfx5preCFX-Pre

See Starting the CFX-Solver from the Command Line (p. 121)in the ANSYS CFX-Solver Manager User's Guide.

cfx5solveCFX-Solver Manager

See Starting CFD-Post (p. 19) in the ANSYS CFD-Post User'sGuide.

cfdpostCFD-Post

To display a full list of all the possible arguments and a short description for any command, type the command followedby -help. For example:

cfdpost -help

Typing the argument -verbose after a command launches the software specified and displays a summary of thecurrently set environment variables.

Obtaining System Information with the cfx5info CommandYou can use the command cfx5info to obtain information about your installation and your system. The optionalcommand arguments are given in the following table:

UsageArgument

Displays the long architecture string for the current machine.-arch

Prints the location of some common commands, if they can be found in the PATH.-cmds

If any site-specific or user-specific configuration files are in use, this option will displaytheir locations and contents.

-config

Displays a full report on the installation and configuration of CFX, suitable for emailingto the CFX support desk. This includes the output of the -inst and -system options.

-full

Shows available command line options and descriptions.-help

Displays the current host name.-host


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UsageArgument

Looks up the named <host> in the network database, and displays some informationabout it.

-host-addr <host>

Displays information about the installation directory, and available versions of CFX.This is the default if no arguments are passed.

-inst

Displays the short architecture string for the current machine.-os

Shows information for all installed patches.-patches

Displays the release type, which will be “development,” “prerelease” or “release.”-reltype

Shows information about which subsets are installed. This option is valid only forUNIX platforms.

-subsets

Displays information about the system on which CFX is running.-system

Prints information about the environment variables that are currently set. An alternativeform for this argument is -v

-verbose

Displays all available versions of <cmd>, as found on the PATH. This option can berepeated.

-whereis <cmd>


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Chapter 3. What's New in CFXThis chapter describes:

• New Meshing Application:

The new Meshing Application within ANSYS Workbench provides access to many ANSYS meshing tools in asingle location. In the Meshing Application, a different "Meshing Method" (for example, CFX-Mesh, Sweeping,hex-dominant) can be applied to each Part in the geometry.

• Fluid Structure Interaction in ANSYS Workbench:

This release allows set up of a full two-way Fluid Structure Interaction simulation (coupling the ANSYS and CFXsolvers) within ANSYS Workbench.

• Turbomachinery:

TurboSystem allows the automatic set up of a single-blade-passage TurboMachinery simulation in ANSYSWorkbench. This includes BladeGen, CFX-Mesh, and improved capability in Turbomachinery Pre- andPost-processing. Project page tasks automate the ‘Geometry-to-Post-processing' workflow and include a varietyof report templates.

• CFX DesignXplorer (CFX-DX):

The ability to set up CFX parametric studies within ANSYS Workbench has been added as a demonstration feature.You can use expressions to define input and output parameters.

New Meshing Application and Automatic VirtualTopologyA new Meshing Application in ANSYS Workbench provides access to many of the ANSYS meshing tools in a singlelocation. A different “Meshing Method” can be applied to each part in the geometry. All meshes will be written backto a common database (.cmdb) that can be opened in CFX-Pre. The available Meshing methods are: Automatic, AllTet, Hex dominant, Sweep, and CFX-Mesh. CFX-Mesh integration enables you to launch CFX-Mesh on a part in aseparate tab using a right-click operation. Volume Mesh can be generated in CFX-Mesh and committed back to theMeshing Application. These meshing capabilities are also available in the standard Simulation tab (correct licensesrequired).

A meshing options panel that appears when the meshing application is first opened and the ANSYS Workbenchpreferences area enable you to set a preferred meshing method. CFX customers should use CFX-Mesh or the PatchIndependent mesher as their preferred method.

Automatic Virtual TopologyAutomatic Virtual Topology, a “one-click” method of creating groups of virtual faces, is available in the MeshingApplication and in the CFX-Mesh tab. Automatic VT respects Named Selections and existing controls (that is, inflation,face controls, etc.).

Physical Models and Solver Improvements

CFX Compiler in WindowsThe CFX compiler for Windows is Intel Fortran 9.0.


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ANSYS FSI CouplingIt is now possible to fully set up FSI cases, end-to-end, inside the ANSYS Workbench environment. The new streamlinedworkflow includes setting up the mechanical analysis in the Simulation tab, defining the complete FSI setup in CFX-Pre,starting ANSYS and CFX solvers, monitoring data in CFX-Solvermgr;, and finally viewing ANSYS and CFX resultsfiles in CFD-Post.

In addition to the standard profile preserving interpolation available in ANSYS CFX 10.0, a fully conservative,profile-preserving interpolation option has been implemented in ANSYS CFX 11.0. This option is enabled by defaultfor transfers of conservative variables such as force or heat flows. The new option enforces local conservation of thetransferred variable as well as the integrated total force and heat flow for the entire interface. The new option is morerobust to gaps, mesh density changes, and non-overlap regions. Non-overlap regions are treated with zero flux boundaryconditions within CFX-Solver.

Moving Mesh ExtensionsA significant capability in CFX-11.0 is the extended support of Moving Mesh with General Grid Interfaces. By default,the mesh displacements are coupled through interfaces while maintaining the geometrical consistency of the two sidesof the interface.

In addition, Built-in mesh stiffness options are available that enable you to increase stiffness near small volumes orboundaries.

The Moving Mesh capability has been extended to support steady-state Moving Mesh in addition to transient simulations.Second-order transient calculations have been significantly improved; this is particularly important for closed systemswhere conservation of initial mass is now ensured.

Problem Size and Efficiency ImprovementsA new large-problem partitioner that uses 64-bit integers has been introduced. The new partitioner can be accessedfrom the Solver Manager and is capable of partitioning cases with more than 100 million nodes (on computer hardwarethat has enough memory). As of release it has been tested on cases with up to 1 billion tetrahedral elements in a singledomain.

Other improvements in CFX-11.0 include better scaling for multidomain cases. The improvements are most notablein cases that have a large number of ‘Stage' interfaces. Best performance is achieved with the multidomain coupledpartitioning option available on the advanced controls tab in CFX-Solver Manager. Simulations with a large numberof GGIs will also have a significantly reduced memory requirement for partitioning and the CFD simulation.

HP MPI Run Modes have been upgraded on all Linux platforms to use the latest version of HP MPI. All high speedinterconnects supported by HP MPI are supported by CFX on linux ia32, linux amd64 and linux ia64, This currentlyincludes TCP/IP (Ethernet), luDAPL, VAPI, OpenFabrics (IB), GM-2, MX (Myrinet), Elan4 (Quadrics), QLogicInfiniPath, and EtherFabric (Level 5 Networks).

Expression Language AdvancesSeveral improvements have been made to CFX Expression Language (CEL) functionality in this release. Non-attachedregions (regions that have not been used for boundary conditions, domains, or subdomains) can now be used as locatorsfor evaluating integrated quantity functions (for example, massFlow or massFlowAve).

New CEL functions were added to CFX-11.0. These include a new type of function similar to the “subdomain” function:inside()@<Locator>. This function evaluates to unity when evaluated at points within the specified locator.

Particle Tracking ExtensionsTransient Lagrangian Particle Tracking functionality has been extended to allow modeling Transient Particle Trackingwith Moving Mesh.


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New primary breakup spray injector models include BLOB, Enhanced BLOB, and the LISA model. They are availablevia “Cone with Primary Breakup” Particle injection. Using the BLOB Model, atomization and break-up within aprimary break-up zone can be simulated by injecting spherical droplets of uniform size. The Enhanced BLOB Modelallows the droplets to dynamically change size and have different injection velocities due to nozzle cavitation.

The LISA model, or Linearized instability Sheet Atomization, is mostly used for direct-injection spark-ignition enginesand is also available from the GUI.

For transient simulations with Lagrangian particles, it is very helpful to define integrated quantities. Penetration-depthpost-processing for transient particles has been added to allow easy access to spray diagnostics.

Turbulence ModelingA significant addition in CFX-11.0 is the SAS (Scale Adaptive Simulation)-SST model. The main use of this modelis for unsteady CFD simulations, where steady-state simulations are not of sufficient accuracy and do not properlydescribe the true nature of the physical phenomena. Cases which may benefit from using the SAS-SST model wouldinclude unsteady flow behind a car or strong mixing behind blades and baffles inside stirred chemical reactors, unsteadycavitation inside vortex core (fuel injection system) or fluid-structure interaction (unsteady forces on bridges, wings,etc.).

For these problems and others, the SAS-SST model provides a more accurate solution than URANS models, wheresteady-state simulations are not of sufficient accuracy and do not properly describe the true nature of the physicalphenomena

Transition turbulence has been improved and in CFX-11.0; it is fully supported for multiphase flows.

Combustion and Radiation ImprovementsSeveral extensions to Reacting Flow modeling are introduced in CFX-11.0:

• Eddy-dissipation maximum-flame temperature modifications enable you to stop a reaction below a specifiedtemperature limit.

• The 'Partially premixed and laminar Flamelet PDF' combustion model now runs an alternative mixture fraction -reaction progress treatment called the ‘Weighted Reaction Progress' Model. It has a significantly improved mechanismfor primary/secondary air mixing while maintaining backwards compatibility with the previous treatment. SeveralTurbulent Burning velocity correlations can be used: Zimont, Peters, and Muller.

• Chemistry (NOx) post-processing is a significant addition to CFX-11.0: pollutants are solved at the end of the run,so this is a truly post-processing step that is faster and more efficient than directly including NOx reactions withinthe chemistry.

• A spark ignition model for transient simulations has been implemented which is appropriate for specifying thelocation of conditions to start the combustion process. The model describes the initial growth of the spark kerneluntil the mesh can adequately resolve the start of the combustion process.

Improvements to radiation in CFX-11.0 include faster run times for Monte Carlo and the DTM radiation solver, andnoticeable speed improvements for Radiation simulation with GGI interfaces.

A new Thermal Radiation Transfer mode option has been added. This controls whether the Radiation solver runs in a‘Surface to Surface' or ‘Participating Media' mode. The 'Participating Media' mode is the same as what was availablein previous releases. The ‘Surface to Surface' option is an enhancement for non-participating media cases and workswith both DTM and Monte Carlo models. This mode neglects the volumetric radiation sources due to emission andabsorption. Volumetric source effects are neglected by coarsening the radiation mesh to include only the smallestpossible number of volumetric radiation elements, while keeping the full boundary mesh.


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Domain InterfacesThere have been a number of extensions to domain interfaces in CFX-11.0. The most significant is the support ofperiodic GGI with specified pressure change or mass flow rate. Using this new functionality, fully developed ductflow, flows through tube banks, or screens/fans can be modeled at interfaces.

Boundary Conditions and Boundary SourcesIncremental improvements have been made to the specification of boundary conditions. Total Enthalpy boundaries forenergy equation can now be used for all flow regimes and support the following material types: ideal gas, real gas, wetsteam, mixtures. Dry or wet compressible flow cases with phase change can both be modeled using this boundarycondition. 'Zero Gradient' inlets has been extended for volume fraction equation in CFX-11.0. These inlets are applicablefor MPF cases, specifically Free Surface problems. The availability of Boundary source terms has been extended toinlets and outlets in CFX-11.0.

Eulerian Multiphase ExtensionsThere have been a number of model extensions within Eulerian Multiphase models in CFX-11.0. A Non-EquilibriumNucleation model has been implemented that supports one gas phase with dispersed liquid droplet phases (morphologyfor dispersed phase can be set in the interface to ‘Droplets with Phase Change'). A homogeneous nucleation modelautomatically computes the number and location of where droplets form. The diameter distribution is predicted assumingthat the droplets are monodisperse. Both homogeneous (single velocity field) and inhomogeneous (velocity field foreach phase) multiphase can be used with this model.

Further, a new equation of state for Water, the IAPWS-IF97 industrial standard, has been added. This equation of stateprovides built-in properties for:

• Superheated vapor

• Compressed liquid

• Supercritical fluids

• Liquid and vapor saturation properties

• Metastable vapor and liquid properties.

This model can be used for modeling both equilibrium and non-equilibrium boiling, cavitation, evaporation, andcondensation, in addition to single-phase dry steam simulations.

Significant Multiphase numeric improvements have also been made for Free Surface calculations by adding a CoupledVolume Fraction (CVF) non-linear iterative strategy. This method strictly couples V, P, and volume fractions. TheSegregated coupling algorithm (SVF) is still the default, but CVF can be easily activated in the GUI on the solvercontrols tab. It has been found to be especially effective on free surface flow applications.

CFX-PreAs well as supporting all new physical models, CFX-Pre offers continued improvements in usability and performancefor CFD physics pre-processing:

Region Creation and Editing:The ability to create/edit 2D regions by picking mesh faces has been introduced. A variety of picking modes areavailable: face, flood and polygon.

Usability:The new design removes clutter from the interface, simplifies your view of the simulation, and makes the producteasier to use. New tree presentation and actions have been introduced and right-click options in the tree are context-based.


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The tabbed workspace has also been overhauled for this release. All physics editors are now embedded as tabs andthere are fewer pop-ups.

‘Viewer right-click' for creation and editing of objects options are available.

Quick setup mode has been extended to support ‘Multi-component' and ‘Multiphase' flows. Inlet and Outlet boundariesare auto-created.

Default Domain and Interface GenerationWhen a mesh is imported, a ‘Default Domain' is created encapsulating all of the 3D mesh regions that are currentlyunassigned. This complements the ‘Default Boundary' mechanism from previous releases. In addition, ‘Default DomainInterfaces' are generated between (and within) domains where their regions are topologically connected. The ANSYS‘Contact Detection' capability is used to determine where meshes are in contact. These interfaces are generateddynamically when a domain of boundary changes, rather than at the ‘Write Solver Input File' stage, as in previousreleases of the software.

CFD-PostCFX-11.0 contains a number of new features that represent significant advancements in the interactivity and usabilityof working within CFD-Post: automatic report generation, saving of plots as figures, the ability to load multiple resultsfiles, ANSYS structural results support, the ability to add timesteps, magnification of mesh displacements, and theability to modify solution variables. Details are given below.

ANSYS .rst file support:CFD-Post supports loading and post-processing of ANSYS files: .rst, .rth, .rmg, and .rft. Transient ANSYSdata can be processed and displacement magnification is available. Shell Elements are also supported.

Multiple Data files:Two or more data files can now be loaded into Post in a single session. An offset can be applied for viewing. This isa very useful feature for loading both CFX .res files and ANSYS .rst (or other formats) results files, and viewingthem in the same session. Global Variable ranges are common to all files.

Immediate mode object dragging:When dragging planes, isosurfaces, or lines, the object gets recalculated on-the-fly and not only when releasing thebutton.

Report generation:All charts, tables, figures, and comments automatically become report content. The report component order can beadjusted and figures can be 3D Viewer files or bitmaps. Different output formats are available, including HTML.

Turbo Post:The Turbo Post environment now includes Mass and Area weighted distributions of Hub-Shroud points. Also, a newBlade Aligned Streamwise Location coordinate can be used to align the Hub-Shroud lines with the leading and trailingblade edges.

Replacing of solution variables with expressions:Any solution variable can be redefined in CFD-Post 11.0 via an expression and written back to the results file. This issupported only for CFX files, not for timesteps or in multifile mode.


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Beta FeaturesANSYS CFX 12.0 includes Beta Features. These features have received limited testing and are provided for yourcomments. Refer to the CFX Release Notes for details.

Supported PlatformsThe following table outlines the operating system and platform support for CFX-11.0:

Supported Operating SystemsVendor/Chip

CFX in ANSYS WorkbenchCFX Standalone

Solaris 9/10Solaris 9/10Sun (UltraSPARC)

AIX 5.3IBM (Power RISC)

Tru64 Unix 5.1 (Solver only)HP-Compaq

HP-UX 11i v1HP-UX PA-RISC

HP-UX 11i v2Intel Itanium 2 (IA 64) -HPUX

Red Hat Enterprise Linux 3Intel Itanium 2 (IA 64) -Linux

Red Hat Enterprise Linux 4

SLES 9.x

SGI Propack 3/4

Windows XPWindows XPIntel IA32 and AMD Athlon

Windows 2000Windows 2000

Red Hat Enterprise Linux 3Red Hat Enterprise Linux 3


SLES 9.xSLES 9.x

SuSE Professional 9.xSuSE Professional 9.x/10.0

Windows XP 64Windows XP 64Intel IA64 and AMD Athlon



SLES 9.xSLES 9.x

SuSE Professional 9.xSuSE Professional 9.x/10.0


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Chapter 4. Customizing ANSYS CFXThis chapter discusses:

• ANSYS CFX Resource Configuration Files (p. 25)

ANSYS CFX Resource Configuration FilesWhen ANSYS CFX starts up, it reads several resource configuration files. By creating your own local and site-wideconfiguration files, you can modify the behavior of ANSYS CFX to meet your needs. A common use for configurationfiles is to set the path to the license file or the license server.

The Site-wide Configuration FilesIf you are accessing your ANSYS CFX files from a remote file system, your System Administrator may create site-wideresource configuration files. ANSYS CFX first looks for such files in the following order:

1. <CFXROOT>/config/cfx5rc-<host>.txt

2. <CFXROOT>/config/cfx5rc-<arch>.txt

3. <CFXROOT>/config/cfx5rc-<os>.txt

4. <CFXROOT>/config/cfx5rc.txt

5. <CFXROOT>/config/cfx5rc-site.txt

where:

• host is the hostname of the machine on which ANSYS CFX is running.

• arch is the architecture of the machine on which ANSYS CFX is running.

• os is the operating system of the machine on which ANSYS CFX is running.

You can find the value of host, arch, and os by selecting Show > Show System from the menu bar of the CFX Launcher.On Windows, the value of os is winnt.

NoteAny resources set in these files will affect all users of ANSYS CFX, unless users override these variablesin their personal user's ANSYS CFX resource configuration files.

User's Configuration FilesAfter searching for site-wide configuration files, ANSYS CFX looks for the following user's configuration files:

• cfx5rc-<host>.txt

• cfx5rc-<arch>.txt

• cfx5rc-<os>.txt

• cfx5rc.txt

(and for the same files without .txt appended) in the following directories:

• On Windows: %USERPROFILE%\Application Data\CFX-5\12.0\ if it exists,otherwise%HOMEDRIVE%\%HOMEPATH%\.cfx\12.0\ where %USERPROFILE%, %HOMEDRIVE% and%HOMEPATH% are environment variables.

.

• On UNIX: ~/.cfx/12.0/ and ~/CFX/12.0/


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where ~ means your home directory (if you have one).

Syntax of CFX Resource Configuration FilesANSYS CFX resource configuration files should consist only of:

• Lines beginning with # (which are comments).

• Variable assignments such as: CFX5EDITOR="textedit"

The right hand side of an assignment may include references to previously assigned variables by prefixing the variablename with $; for example,

CFX5BROWSER="$CFX5EDITOR"

NoteIn previous releases of ANSYS CFX, these files could contain arbitrary Bourne shell commands. These areno longer supported.

Resource NamesANSYS CFX software makes use of variable names that start with the following strings:

• CFDS_

• CFX_

• CFX4

• CFX5

• CUE_

You must not set any variable of your own with a name beginning with these letters.

Resources Set in cfx5rc FilesYou can find out which ANSYS CFX resources have been set by using the Show > Show Variables option from themenu bar of the CFX Launcher. This displays a list of all the resources that have been set. Although you can changethe values of most of the resources shown in this list, it is generally useful to change only a few of them. These feware described in the following table:

DescriptionResource

Sets the program to use when browsing files in ANSYS CFX.CFX5BROWSER

On Windows, the default browser is Notepad.

On UNIX, the default value is system-dependent, but the Common DesktopEnvironment file browser, dtpad, is used if possible. The command must start itsown X window, so if you wanted to use view, for example, you could only do so bysetting

CFX5BROWSER="xterm -e view"

Sets the program to use when editing files in ANSYS CFX.CFX5EDITOR

On Windows, the default editor is Notepad.

On UNIX, the default value is system-dependent but the Common DesktopEnvironment file editor, dtpad, is used if possible. The command must start its ownX window, so if you wanted to use vi, for example, you could only do so by setting


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DescriptionResource

CFX5EDITOR="xterm -e vi"

Creates a window to interact with the operating system.CFX5XTERM

On Windows, the default window is a Windows command prompt set up to run theANSYS CFX commands.

On UNIX, the default value is system-dependent but the Common DesktopEnvironment terminal emulator, dtterm, is used if possible.

If set to F, this command causes ANSYS CFX programs to write formatted CFX-Solverinput and results files instead of binary files.

CFX_FORMAT

If set to U, then the files generated will be in binary format, but not compressed.

If not set, then the files generated will be binary and compressed. This is the default.

Sets the name of the user-defined executable for CFX Volume Mesh Import.CFX_IMPORT_EXEC

This is a colon-separated list of directories which will be searched for shared librarieson Sun and Compaq Tru64 UNIX systems. If you have installed system libraries indirectories that are not included in this list, use this command to add these directories.

LD_LIBRARY_PATH

This is a colon-separated list of directories which will be searched for shared librarieson SGI systems. If you have installed system libraries in directories that are notincluded in this list, use this command to add these directories.

LD_LIBRARYN32_PATH

This is a colon-separated list of directories which will be searched for shared librarieson IBM systems. If you have installed system libraries in directories that are notincluded in this list, use this command to add these directories.

LIBPATH

If you have license keys in a file other than <CFXLICENSEROOT>/license.dat,you may have to set the value of this resource to be either

LM_LICENSE_FILE

i) port@host where the license daemon is listening for requests on port number porton the machine called host

or

ii) the full pathname of the license file.

This is a colon-separated list of directories that will be searched to look for sharedlibraries on HP systems. If you have installed system libraries in directories that arenot included in this list, then add them to it.

SHLIB_PATH

Setting Environment VariablesYou should set the variables in your cfx5rc file. You must not create environment variables that start with CFX.


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Chapter 5. Using the CFX LauncherCFX can be run in two modes:

• CFX Standalone, which refers to CFX running as a standalone application independent of the ANSYS Workbenchsoftware

• CFX Workbench, which refers to CFX running as a component inside of the ANSYS Workbench software. Thisis described in ANSYS CFX in ANSYS Workbench (p. 31).

CFX Standalone has the CFX Launcher, which makes it easy to run all the modules of CFX without having to use acommand line. The launcher enables you to:

• Set the working directory for your project

• Start CFX and ANSYS products

• Access various other tools, including a command window that enables you to run other utilities

• Access the online help and other useful information

• Customize the behavior of the launcher to start your own applications.

The CFX Launcher automatically searches for installations of CFX and ANSYS products including the license manager.Depending on the application, the search includes common installation directories, directories pointed to by environmentvariables associated with CFX and ANSYS products, and the Windows registry. In the unlikely event that a productis not found, you can configure the CFX Launcher using steps outlined in Customizing the Launcher (p. 16).


• Starting the CFX Launcher (p. 29)

For more information about the launcher, see The Launcher Interface (p. 13) and Customizing the Launcher (p. 16).

Starting the CFX LauncherYou can run the CFX Launcher in any of the following ways:

• On Windows:

• From the Start menu, go to All Programs > ANSYS 12.0 > CFX > ANSYS CFX 12.0.

• In a DOS window that has its path set up correctly to run CFX, enter cfx5 (otherwise, you will need to enterthe full pathname of the cfx5 command).

• On UNIX, enter cfx5 in a terminal window that has its path set up to run CFX.


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Chapter 6. ANSYS CFX in ANSYSWorkbenchANSYS CFX components can be run in two modes:

• As standalone applications started from the ANSYS CFX Launcher and independent of the ANSYS Workbenchsoftware. This mode is described in Using the CFX Launcher (p. 29).

• As components launched from ANSYS Workbench as required to solve fluid flow (CFD) problems.

This chapter describes using ANSYS CFX in ANSYS Workbench:

• The ANSYS Workbench Interface (p. 31)

• An Introduction to Workflow within ANSYS CFX in ANSYS Workbench (p. 36)

• Known Limitations of Using ANSYS CFX in ANSYS Workbench (p. 39)

NoteThis chapter assumes that you are familiar with using ANSYS CFX in standalone mode. You should consultthe ANSYS Workbench help for more detailed information on ANSYS Workbench.

TipFor examples of using ANSYS CFX in ANSYS Workbench, see the following tutorials:

• Oscillating Plate with Two-Way Fluid-Structure Interaction (p. 391) in ANSYS CFX Tutorials

• Aerodynamic & Structural Performance of a Centrifugal Compressor (p. 429) in ANSYS CFX Tutorials

The ANSYS Workbench InterfaceYou launch ANSYS Workbench from the Start menu. The full path is Start > All Programs > ANSYS 12.0 > ANSYSWorkbench.

The ANSYS Workbench interface is organized to make it easy to choose the tool set that will enable you to solveparticular types of problems. Once you have chosen a system from the Toolbox and moved it into the Project Schematic,supporting features such as Properties and Messages provide orienting information. These features and the statusindicators in the system cells guide you through the completion of the System steps.

The figure that follows shows ANSYS Workbench with a Fluid Flow (CFX) analysis system open and the propertiesof cell A2 (Geometry) displayed:


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The following sections describe the main ANSYS Workbench features.

ToolboxThe Toolbox shows the systems available to you:

Analysis SystemsSystems that match the workflow required to solve particular types of problems. For example, the Fluid Flow(CFX) system contains tools for creating the geometry, performing the meshing, setting up the solver, using thesolver to derive the solution, and viewing the results.

Component SystemsSoftware elements upon which Analysis Systems are based. For example, the CFX component system containsSetup (CFX-Pre), Solution (CFX-Solver Manager), and Results (CFD-Post). The Results component systemcontains only Results (CFD-Post).

Custom SystemsSystems that combine separate analysis systems. For example, the FSI: Fluid Flow (CFX) > Static Structuralsystem combines ANSYS CFX and Mechanical to perform a unidirectional (that is, one-way) Fluid StructureInteraction (FSI) analysis.

Design ExplorationSystems that enable you to see how changes to parameters affect the performance of the system.


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NoteWhich systems are shown in the Toolbox depends on the licenses that exist on your system. You can hidesystems by enabling View > Toolbox Customization and clearing the check box beside the name of thesystem you want to hide.

To begin using a system, drag it into the Project Schematic area.

Project SchematicThe Project Schematic enables you to manage the process of solving your CFD problem. It keeps track of the yourfiles and shows the actions available as you work on a project. At each step you can select the operations that processor modify the case you are solving.

When you move a system from the Analysis Systems toolbox to the Project Schematic, you will see a set of toolssimilar to the following:

Each white cell represents a step in solving a problem. Right-click the cell to see what options are available for you tocomplete a step.


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Many cells launch specialized software that enables you to perform the task required by that step. For example, in aFluid Flow (CFX) system:

• Geometry > New Geometry launches DesignModeler.

• Mesh > Edit launches the Meshing Application (from which you have the option of running CFX-Mesh).

• Setup > Edit launches CFX-Pre.

• Solution > Edit launches CFX-Solver Manager.

• Results > Edit launches CFD-Post.

View BarYou control which views are displayed by opening the View menu and setting a check mark beside the view you wantto display. If you minimize that view, it appears as a tab in the View Bar and the check box is cleared from the Viewmenu.

Properties ViewThe Properties view is a table whose entries describe the status of a system. These entries vary between system cellsand are affected by the status of the cell. Some entries in the Properties area are writable; others are for informationonly.

To display the Properties for a particular cell, right-click on the cell and select Properties. Once the Properties viewis open, simply selecting a cell in the Project Schematic will display that cell's properties.

The following properties are specific to ANSYS CFX components:

Setup Cell Properties

Provides information about the current settings in ANSYS CFX-Pre and describes howto adjust them.

Physics Status

Solution Cell Properties


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Update from Current Solution Data if possible causes ANSYS CFX-Solver Managerto use the physics and mesh information from the previous solution run (if these exist)and to generate a new CFX-Solver Results file.

Initialization Optiona

If there is no previous solution run, ANSYS Workbench will also check for the existenceof an upstream solution cell and for the presence of Initial Values definitions on the DefineRun dialog of ANSYS CFX-Solver Manager.

NoteThis is the default setting, which is not desirable for the second and subsequentupdates of transient cases, for starting from initial conditions provided byanother system, or for a situation in which you have divergent results and donot want to start an update from those bad results.

Update from Initial Conditions causes ANSYS CFX-Solver Manager to use the physicsand mesh information from the current state of the Setup cell.

Controls whether the update proceeds as a Background Task or a Foreground Task.Update Option

Choose Load only the last results to load only the last configuration of amulti-configuration results file, or only the last results from a results file that contains arun history, into CFD-Post.

Multi-configuration PostProcessor Load Options

Choose Load complete history as: a single case to load all configurations of amulti-configuration run as a single case, or all of the results history from a results file thatcontains a run history. In either case, only one set of results will appear in the CFD-Postviewer, but you can use the timestep selector to move between results. This option is notfully supported.

Choose Load complete history as: separate cases to load all configurations from amulti-configuration run into separate cases. If a results file with run history is loaded,CFD-Post loads the results from this file and the results for any results file in its run historyas separate cases. Each result appears as a separate entry in the tree.

Results Cell Properties

Select this check box to automatically publish a report. The location of the report isdisplayed in the Files view.

Generate Report

aThis setting synchronizes interactively with changes in the Initialization Option setting in the ANSYS CFX-Solver Manager's Define Run dialog.

Files ViewThe Files view shows the files that are in the current project. The project files are updated constantly, and any “save”operation from the ANSYS CFX components will save all files associated with the project.


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Sidebar Help

In addition to having a visual layout that guides you through completing yourproject, you can also access Sidebar Help by pressing F1 while the mouse focusis anywhere on ANSYS Workbench. Sidebar Help is a dynamically generatedset of links to information appropriate for helping you with questions you haveabout any of the tools and systems you currently have open.

Shortcuts (Context Menu Options)You can access commonly used commands by right-clicking in most areas of ANSYS Workbench. These commandsare described in the section Context Menu Options in the ANSYS Workbench help. In addition to those shortcuts, thereare commands that are specific to CFX Solution cells:

Display MonitorsOpens the ANSYS CFX-Solver Manager and shows the results of the previous run.

Import SolutionDisplays the Open dialog, where you can specify the CFX Solver Results file to load. When the results file isloaded, the system will display only the Solution cell and the Results cell.

Continue CalculationPerforms an update of the Solution cell, completing a previously stopped run (if one is available), or otherwiserestarts the current run.

Clear Execution ControlWhen a solver run is started, the settings from the Define Run dialog are stored for the Solution cell that launchedthe solver; these are the execution control settings for that cell. The Clear Execution Control command removesthose settings.

An Introduction to Workflow within ANSYS CFXin ANSYS WorkbenchThis section walks through an example of using ANSYS CFX in ANSYS Workbench to perform a fluid-flow analysis.This walkthrough assumes familiarity with the basic ANSYS Workbench and ANSYS CFX applications and does notdiscuss the details of the steps within each application.

The data flow between cells (and systems) drives the workflow.


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1. You begin by launching ANSYS Workbench, which opens as an unsaved project and displays the availableanalysis systems.

2. In your file system you create a directory in which to store your project files. You then select File > Save As andsave your new project to that directory. This automatically sets your working directory for this project.

3. In the Analysis Systems toolbox, double-click on Fluid Flow (CFX) to create a fluid-analysis system in theProject Schematic. (Notice that if you “hover” over systems in the Toolbox, a tool tip appears.)


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The fluid-analysis system in the Project Schematic shows the steps in performing a fluid analysis:

1. Create or import a geometry.

2. Create a mesh for the geometry.

3. Set up the analysis that will be sent to the solver.

4. Control and monitor the solver to achieve a solution.

5. Visualize the results in a post-processor and create a report.

4. In addition to showing those steps in appropriately named cells, each cell can launch a tool that will enable youto perform the task it names. Right-click on the Geometry cell to see your options for adding a geometry to yourproject:

5. As you move through the cells from Geometry to Results, you can choose to launch the tool that will enable youto complete the cell's step: create a new geometry with ANSYS DesignModeler, create a new mesh with ANSYSCFX-Mesh, edit the case with ANSYS CFX-Pre, control the solver's solution with ANSYS CFX-Solver Manager,and control the display of the results with ANSYS CFD-Post.

NoteYou could open a Fluid Flow (CFX) system and go immediately to the Setup cell to import an existingcase. When the case is loaded, the now-unnecessary Geometry and Mesh cells disappear.


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6. When the analysis is complete and the project is finished, you save the project (and therefore the associated files).Once a project has been saved, it can be re-opened at a later date for review or modification of any aspect of thesimulation.

Data Flow in Systems and Between SystemsThe cells in a system communicate status with each other. For example, when you change a mesh in the Mesh cell,the Setup cell will report that its software (CFX-Pre) requires a refresh to re-read the “upstream” data.

Similarly, the same type of data flow occurs between systems. For example, if you have an FSI: Fluid Flow system(as shown in the image below), data and status from the Fluid Flow (CFX) Geometry cell will flow both to the FluidFlow (CFX) Mesh cell and the Static Structural (ANSYS) Geometry cell. Data flow between systems is shown byinterconnecting lines:

Known Limitations of Using ANSYS CFX inANSYS WorkbenchThe general use of ANSYS CFX in ANSYS Workbench is known to be limited by the following:

• CFX-Pre and CFD-Post can play session files (or tutorial session files) when launched from ANSYS Workbenchonly when you have enabled Beta features in CFX-Pre or CFD-Post.

• You must use absolute paths for CFX-Solver runs making use of user FORTRAN in ANSYS CFX in ANSYSWorkbench.

• The Units on the settings on the ANSYS Workbench menu bar have no effect on the units used in ANSYS CFXapplications.

• Generating a volume mesh for a Mesh cell does not update the cell or the project. This is because you will oftenwant to generate a mesh without going through the time-consuming process of writing all of the project files.

The use of ANSYS CFX in ANSYS Workbench for multi-configuration simulations is known to be limited by:

• The way that multi-configuration files and transient files open in CFD-Post must be set beforehand in CFD-Postor in the Properties settings for the Solutions cell; you cannot configure these settings from a Results cell.

• • Avoid editing the Solution cell for solved or user-interrupted multi-configuration simulations; this will corruptthe Execution Control CCL. Make any necessary changes by editing the Setup cell (that is, by using CFX-Pre).If the CCL has been corrupted in this way, an error will be generated when the simulation is continued. Repair thecorrupted CCL by selecting one of the following options from the right-click menu of the Solution cell:

• Clear Execution Control: restore the execution control to their previous values.


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• Reset: return the Solution cell to its initial unsolved state (and then re-solve the entire simulation using thecorrected execution control settings).


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Chapter 7. Help On HelpThis chapter discusses:

• CFX Documentation Structure (p. 41)

• Document Conventions (p. 42)

• Accessing Online Help (p. 44)

• Using the Help Browser Index (p. 44)

• Using the Search Feature (p. 45)

• Bookmarking Useful Help Pages (p. 45)

CFX Documentation StructureThe CFX documentation can be found in PDF form in<CFXROOT>..\commonfiles\help\en-us\CFX\help\pdf\ on Windows and in<CFXROOT>../commonfiles/help/en-us/CFX/help/pdf/ on UNIX. In the PDF names that follow, “*”can be:

• fp for ANSYS CFD-Post

• x for ANSYS CFX

For example, fptutr.pdf is the ANSYS CFD-Post Tutorials; xtutr.pdf is the ANSYS CFX Tutorials.

PDF NameDescriptionBook

n/aHow to install CFXInstallation Guide

*rel.pdfHow to import a mesh and specify all of the settingsrequired to write a CFX-Solver input file for theCFX-Solver

Release Notes

xintr.pdfAn overview of CFD and the CFX softwareANSYS CFX Introduction

*tutr.pdfA set of tutorials that demonstrate the workflowTutorials

xmod.pdfHow to use the physical models implemented in theCFX-Solver

CFX-Solver Modeling Guide

xthry.pdfDescribes the mathematical details of the models usedin the CFX-Solver and also how the CFX-Solversolves flow equations

CFX-Solver Theory Guide

xmgr.pdfHow to use the CFX-Solver Manager to control aCFD simulation

CFX-Solver Manager User'sGuide

fpuser.pdf,xpost.pdf

How to post-process a results file (fppost.pdf is forthe standalone version of ANSYS CFD-Post;xpost.pdf is for ANSYS CFD-Post in ANSYS CFX)

ANSYS CFD-Post User'sGuides

xpre.pdfHow to use ANSYS CFX-Pre, the pre-processor forANSYS CFX

ANSYS CFX-Pre User's Guide

*ref.pdfBest-practices guides and complete details for APIs,CFX Command Language, CFX ExpressionLanguage, functions, and variables

Reference Guides


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All documentation is also available in PDF format on the ANSYS Customer Portal. For a link to this web site, or tocontact a CFX representative, see Contact Information (p. 47).

Document ConventionsThis section describes the conventions used in this document to distinguish between text, file names, system messages,and input that you need to type.

Spelling ConventionsANSYS CFX is developed both in North America and Europe, so you will find both American and British spelling:

• atomization and atomisation

• color and colour

• customization and customisation

• discretization and discretisation

• initialization and initialisation

• meter and metre

• normalization and normalisation

• vapor and vapour

• vaporization and vaporisation

When using the documentation's Index, it is useful to search both for American and British spellings. When using thedocumentation's Search function, it is generally best to use American spellings.

Search for:For:

Color Map (or try Color Map Command (p. 164) in ANSYS CFD-Post User's Guide)Colour Map

Color Mode (or try Color Mode (p. 144) in ANSYS CFD-Post User's Guide)Colour Mode

Color Scale (or try Color Scale (p. 33) in ANSYS CFD-Post User's Guide)Colour Scale

Color Tab (or try Color Details Tab (p. 33) in ANSYS CFD-Post User's Guide)Colour Tab

Customization (or try Customization (p. 51) in ANSYS CFX-Pre User's Guide)Customisation

Domain Initialization (or try Domain: Initialization Tab (p. 143) in ANSYS CFX-Pre User'sGuide)

Domain Initialisation

Global Initialization (or try Initialization (p. 143) in ANSYS CFX-Pre User's Guide)Global Initialisation

Initialization Tab (or try Initialization Tab (p. 120) in ANSYS CFX-Pre User's Guide)Initialisation Tab

Turbo Initialization (or try Turbo Initialization (p. 214) in ANSYS CFD-Post User's Guide)Turbo Initialisation

Auto-initialize (or try Requirements for Initialization (p. 214) in ANSYS CFD-Post User'sGuide)

Auto-initialise

Uninitialize (or try Uninitializing Components (p. 215) in ANSYS CFD-Post User's Guide)Uninitialise

Initialize All Components (or try Initialize All Components (p. 215) in ANSYS CFD-PostUser's Guide)

Initialise All Components

Undefined Color (or try Undefined Color (p. 34) in ANSYS CFD-Post User's Guide)Undefined Colour

Synchronize Camera (or try Case Comparison (p. 209) in ANSYS CFD-Post User's Guide)Synchronise Camera


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File and Directory NamesFile names and directory names appear in a plain fixed-width font (for example, /usr/lib). Note that on UNIX,directory names are separated by forward slashes (/) but on Windows, back slashes are used (\). For example, a directoryname on UNIX might be /CFX/bin whereas on a Windows system, the same directory would be named \CFX\bin.

User InputInput to be typed verbatim is shown in the following convention:

mkdir /usr/local/cfx

Input SubstitutionInput substitution is shown in the following convention:

cfx5 -def <def_file>

you should actually type cfx5 -def, and substitute a suitable value for <def_file>.

Optional ArgumentsOptional arguments are shown using square brackets:

cfx5export -cgns [-verbose] <file>

Here the argument -verbose is optional, but you must specify a suitable file name.

Long CommandsCommands that are too long to display on a printed page are shown with “\” characters at the ends of intermediatelines:

cfx5export -cgns [-boundary] [-corrected] [-C] \ [-domain <number>] [-geometry] [-help] [-name <file>] \ [-summary] [-timestep <number>] [-user <level>] [-norotate] \ [-boundaries-as-nodes|-boundaries-as-faces] [-verbose] <file>

On a UNIX system, you may type the “\” characters, pressing Enter after each. However, on a Windows machine youmust enter the whole command without the “\” characters; continue typing if the command is too long to fit in thecommand prompt window and press Enter only at the end of the complete command.

Operating System NamesWhen we refer to objects that depend on the type of system being used, we will use one of the following symbols inthe text:

<os> refers to the short form of the name which CFX uses to identify the operating system in question. <os> willgenerally be used for directory names where the contents of the directory depend on the operating system but do notdepend on the release of the operating system or on the processor type. Wherever you see <os> in the text you shouldsubstitute with the operating system name. The correct value for a UNIX system can be determined by running:

<CFXROOT>/bin/cfx5info -os

On a Windows system, <os> will always be windows.

<arch> refers to the long form of the name that CFX uses to identify the system architecture in question. <arch> willgenerally be used for directory names where the contents of the directory depend on the operating system and on therelease of the operating system or the processor type. Wherever you see <arch> in the text you should substitute theappropriate value for your system, which can be determined by running the UNIX command:


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<CFXROOT>/bin/cfx5info -arch

Accessing Online HelpThere are several different ways to access the online help system:

• Select one of the appropriate commands from the Help menu of the ANSYS CFX Launcher or ANSYS Workbench.

• Click on a feature of the CFX interface to make it active and, with the mouse pointer over the feature, press the F1key (the Help key on Sun workstations) for context-sensitive help. Not every area of the interface supportscontext-sensitive help.

If CHM Files Cannot be Accessed Over a NetworkMicrosoft Security Update 896358 makes it impossible to view parts of a CHM file that is stored on a network drive,although the CHM Viewer will open. Network Configuration installations typically require you to open the CHM fileon a network shared folder.

If all the computers on your intranet are secure, you can perform the following steps to lower the restrictions on theLocal Intranet zone and thus enable CHM files to display:

1. Click Start > Run. The Run dialog box opens.

2. Type regedit and then click OK.

3. Locate and then click the following subkey:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\HTMLHelp\1.x\ItssRestrictions

If this registry subkey does not exist, create it.

4. Right-click the ItssRestrictions subkey and select New > DWORD Value.

5. Type MaxAllowedZone and then press Enter.

6. Right-click the MaxAllowedZone value, and then select Modify.

7. In the Value data field, type 1 and then click OK.

8. Quit the Registry Editor.

If this solution does not work for you, see http://support.microsoft.com/kb/896358 andhttp://support.microsoft.com./kb/896054 for more information.

Adjusting Font Sizes in Online HelpIf you are viewing the help in UNIX, you can change the font size on your display by tapping + and –.

If you are viewing the help in Windows, you can increase/decrease the font size by holding down the Ctrl key andsliding the mouse wheel up or down.

Using the Help Browser IndexThe Index tab of the help browser allows you to search for index terms and display the associated topics.

To find a topic using the index:

1. In the field at the top, type the first few letters of a keyword. The keyword list scrolls to the relevant keywords asyou type. As keywords are selected, one or more topic titles appears in the topics list below.

2. Select a topic from the list, then click the Display button (Windows) or Open button (UNIX).

Results from the Help index will not be exhaustive, so you should consider using the Search function as well. SeeUsing the Search Feature (p. 45).


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Using the Search FeatureThe Search tab of the help browser enables you to perform searches through the online help.

If you are running on Windows, you can search for a phrase by wrapping the phrase in quotes. In this case, you maywant to turn off the Match similar words option to avoid returning extra search results for phrases made from similarwords.

NoteThe Search titles only option restricts searches to titles of chapters and major sections, but not all sections.

Bookmarking Useful Help PagesWindows users who come across a help page that they expect to refer to in the future can add it to a Favorites page.With the help page displayed, click on the Favorites tab, then click Add.


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Chapter 8. Contact InformationThis chapter discusses:

• How to Contact ANSYS Customer Service (p. 47)

• ANSYS Customer Portal (p. 47)

Technical Support for ANSYS products is provided either by ANSYS, Inc. directly or by one of our ANSYS SupportProviders. Please check with the ANSYS Support Coordinator (ASC) at your company to determine who providessupport for your company. Support provider contact information is available from the ANSYS Customer Service pageon the ANSYS Website (www.ansys.com) under Solutions > Services and Support > Customer Service. The directURL is: http://www.ansys.com/services/ss-customer.asp. If your support is provided by ANSYS, Inc., please use thecontact information listed in the following sections.

How to Contact ANSYS Customer ServiceANSYS aims to provide high-quality software, documentation, and product support. To help achieve this goal, wemaintain technical support centers around the world.

If you have problems contacting any of our offices, please contact:

Select the Support tab on the ANSYS Customer Portal(http://www1.ansys.com/customer)

Web:

1.800.711.7199Toll-Free Telephone:

724.514.3600Telephone:

724.514.5096Fax:

[email protected]

To help us respond quickly to your question, we will request the following information from you:

• Customer information (your name and company name)

• Product and platform information (computer type and operating system; product name and version; and a detaileddescription of the question/problem)

• Any files relevant to your problem.

If you send files via email from a UNIX system, please compress and uuencode the files before sending them.

If you have system-related problems once the software has been installed, information about any local customizationof CFX which may have taken place can be obtained as follows:

Run the CFX launcher, choose the Show > Show All command from the menu, and save the messages to a file. Includethis file with your email.

ANSYS Customer PortalThe ANSYS Customer Portal is available from the ANSYS web site (http://www.ansys.com) by clicking CUSTOMERAREA, then clicking ANSYS Customer Portal on the page that appears. You can also go there directly:http://www1.ansys.com/customer/

One of the many useful features of the Customer Portal is Online Support > Knowledge Base Search, which enablesyou to find solutions to various types of problems, much like an FAQ.


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Documents

ANSYS CFX Introduction