Research in Computational Fluid Dynamics

(CFD)

Department of Mechanical Engineering

R.K. Jaiman, B.C. Khoo, H.P. Lee, N. Phan-Thien,C. Shu, D.S. Tan, C.J. Teo, K.S. Yeo

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Background• Fluid Mechanics plays an extremely crucial role in a wide

variety of commercial and military applications, and in our everyday lives.

• The governing equations in Fluid Mechanics are typically non-linear, time and history dependent.

• Computational Fluid Dynamics (CFD): the sub-branch of Fluid Mechanics which employs numerical tools for solving fluid flow problems

• The NUS Mechanical Engineering (ME) Department has built up a critical mass, with • sustainable research funding• international visibility• industry-based research and outcomes

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CFD Research Objectives (1)(A) Development of novel and efficient numerical methods and

algorithms to solve a wide variety of fluid flow problems.• Examples:(i) Lattice Boltzmann Flux Solver method (LBFS) for solving

multiphase flow problems;(ii) Immersed boundary method (IBM) for solving moving

boundary problems in aquatic swimming and insect flight;(iii) Completed double layer boundary element method for

problems involving suspensions;(iv) Dissipative Particle Dynamics (DPD) method for solving

mesoscale problems and macroscale problems(v) Continuous Boltzmann equation-based flux solvers (gas

kinetic schemes) for low- and high-speed flows

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CFD Research Objectives (2)(B) Application of CFD for fundamental research: To develop new insights in physical flow processes; To complement experimental research work.

(C) Application of CFD for a diverse range of appliedcommercial and defense-related research involving fluid flow processes, especially in the Singapore context.

• Examples of funded research topics/projects:

(i) Aerodynamics and hydrodynamics of Wing-in-Ground (WIG) craft;

(ii) Turbulent drag reduction using dimpled surfaces;

(iii) Novel aerospace propulsion systems, such as Pulse Detonation Engines, cross-flow fans and ducted fans;

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CFD Research Objectives (3)(iv) Flapping wing aerodynamics for application to Unmanned

Aerial Vehicles (UAV);

(v) Supercavitation for high-speed marine craft;

(vi) Fluid flow processes of importance to the Offshore Oil and Gas Industry, such as multiphase flows, flow induced vibration, sedimentation processes, modelling of colloidal, bubble and droplet suspensions and porous media;

(vii) Biofluid dynamics involving applications such as the flow and deformation of red blood cells;

(viii)Hydrodynamics of water and ocean waves, with application to liquid sloshing problems and the dynamic response of marine craft.

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CFD Track Record (1)(A) Publication in Top-Tier Journals related to Fluid

Mechanics and computational methods: • Examples: Journal of Computational Physics,

International Journal for Numerical Methods in Fluids, Journal of Fluid Mechanics, Physics of Fluids, Computers and Fluids.

Many research publications have received high citations.

(B) Securing of Competitive External Research Grants: • Funding Agencies: NRF (NUS-Keppel Corporate Lab),

A*Star, MINDEF, MOE, MPA, Airbus, Office of Naval Research (ONR), ONR Global, Wigetworks Pte Ltd.

Attracted a total of more than $15 million of research funding.

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CFD Track Record (2)(C) Members of Editorial Boards:

• Examples: Editor-in-chief for Advances in Applied Mathematics and Mechanics, Editor-in-chief for book series of “Advances in Computational Fluid Dynamics”, Associate Editor for Communications in Computational Physics, Editorial board member for International Journal for Numerical Methods in Fluids and The Open Mechanical Engineering Journal.

(D) Awards and Prizes:• Examples: Silver Prize, Centenary Medal, Gordon Bell

Prize, Australian Society of Rheology Medal, Edgeworth David Medal

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Numerical Simulation of Unsteady Cavitating Flow

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Dissipative Particle Dynamics in Biophysics

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Flow Over Dimpled Surfaces

Turbulent flow structure inside multiple dimpled channel (streaklines)

Close-up of particle trajectories in dimple - turbulent flow

Flow structures inside a single dimple: laminar flow

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Numerical Simulation of Fish Swimming

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Numerical Simulation of Insect Flight

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Development and Applications of Lattice Boltzmann Method

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Development and Applications of Lattice Boltzmann Method

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The mixture behind the shock wave is self-ignited, which makes the pressure rise and the flow accelerate.

Numerical Simulation of Detonation Waves in Pulse Detonation Engines

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Computational Aerodynamics of Wing-In-Ground (WIG) Craft

0.0

0.2

0.4

0.6

0.8

1.0

1.2

0.00 0.10 0.20 0.30 0.40 0.50 0.60

CL

H/C

CL VS H/C of simplified NAVION wing + tail configuration

AoA=6degAoA=5degAoA=4deg

0.000

0.005

0.010

0.015

0.020

0.025

0.030

0.00 0.10 0.20 0.30 0.40 0.50 0.60

Cd_i

H/C

Induced Drag Cd_i VS H/C for simplified NAVION wing +Tail configuration

AoA=6degAoA=5degAoA=4deg

Normalized Pressure Distribution at H/C = 0.1

AoA = 2°

• Wing-In-Ground (WIG)Effect Craft potentially experience higher lift and lower induced drag than conventional aircraft

• Investigate aerodynamicsand performance of WIG-craft

Wing

Tail

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Numerical Simulations of Cross Flow Fanfor Propulsion

Static Pressure Total Temperature

Relative Mach Number Velocity Vectors

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Wavy Microchannel Heat Sinks For Electronic Cooling Applications

Velocity vectors along cross sections of wavy microchannel with wavy amplitude A = 260 μm at Re = 600 for various axial locations. Lower boundaries correspond to reflection symmetric x-y planes at half depth of channel.

x = 5L x = 5.5L x = 6L

Re = 600

Poincaré sections obtained from tracking 20,000 tracer particles for a wavy channel with A = 260 μm at Re = 600

Signature of chaotic mixing

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Corrugated Pipe for LNG Transfer

Wall-bounded turbulent flowsHybrid RANS/LES (DES) & (DDES) modelsCritical pressure drop

Jaiman and Oakley, OMAE 2010

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High Fidelity Transient Solution of Flow Past Circular Cylinder

Flow over a Cylinder at Reynolds number =140K

Corson and Jaiman, IJCFD 2009

Drag coefficient RMS Lift CoefficientExperiment (CC) 1.24 - 0.18Experiment (WA) 1.3 0.58 -Experiment (SB) 1.35 0.5 -AcuSolve LES 1.27 0.58 0.2

Strouhal Number