aqwa-training-sxd-9

7/24/2019 aqwa-training-sxd-9

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2010 ANSYS, Inc. All rights reserved. 1 ANSYS, Inc. Proprietary


AQWA Training Course

Dr Shuangxing Du

ANSYS Inc.


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The topics covered in the training course are as follows:

description of program capabilities

theoretical background modelling techniques

analysis procedure

data requirements and preparation description of output and interpretation of results

worked examples

Topic


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AQWA Programs

Structure and Capabilities of AQWA ProgramsAQWA LINE

3-D diffraction & radiation analysis program for wave force and

hydrodynamic property calculations; hydrostatic analysis

AQWA LIBRIUM

Structure equilibrium position and force balance calculations; eigen

mode and dynamic stability analysis

AQWA FER

Spectral analysis of structure motion (wave frequency or/and drift

frequency) and mooring tension in irregular waves


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AQWA Programs

AQWA NAUT Time domain program for wave frequency structure motion and

mooring tension analyses in large waves

AQWA DRIFT

Time domain program for drift frequency and wave frequencystructure motion and mooring tension analysis in irregularwaves

AQWA Graphical Supervisor (AGS)

AQWA pre and post processor; on-line analysis

AQWA WAVE Interface program to transfer wave loads from AQWA LINE to a

FE model for structural analysis


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General Relations between Programs

LIBRIUM

WAVE

ASAS(FE model)

ANSYSAGS

FER NAUT DRIFT

LINE

EXCEL


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Moored Tanker

Semi Sub

Typical AQWA Models


7/167 2010 ANSYS, Inc. All rights reserved. 7 ANSYS, Inc. Proprietary

Transportation

FPSO

Spar

Ship in channel

Typical AQWA Models



JACK-UP



FPSO+TLP CONCEPT



MANY SHIPS



SEMI-SUB



LIFTING



GREEN OCEAN ENERGY



ANSYS-to-AQWA Interface



AGS mesh generation



Force & Response Curves

Shear Force & Bending Moment

AGS Post-processing



Pressure contour

Wave surface contour

Diffracted wave surface

AGS Post-processing



InstallationAQWA, AGS and AQWA-WAVEAQWA Manuals and examples

AGS demonstration

Open - Open/close, and save AQWA modelsEdit - Create and edit AQWA models

Run - Perform an AQWA analysis on the presently loaded modelGraphs - Display and manipulate AQWA results graphicallyPlots - Display and edit AQWA models visuallyCable Dynamics - Define and analyze problems involving cable dynamics

Help - Access to the online help system



AQWA Global Coordinate System

AQWA Global Coordinate System is referred to as

the Fixed Reference Axes (FRA):

the origin lies in the still water

plane

the positive z axis is verticallyupwards

a right handed system

it is not related to the directions North, South, East and West

0

z

y

xW.L.

Zp



Hydrostatic

Rigid body motions:Surge, Sway, Heave - translational

Roll, Pitch, Yaw - rotational

Archimedess principle

Buoyancy of an immersed body = weight of the fluid displaced

Hydrostatic pressure

G: centre of gravity

B: centre of buoyancy

Buoyancy is the resultant of all hydrostatic force over wetted surface

0Zp =

0Zp =Z0

G

B

BowStern Port side

Starboard side x

z

y



Directions in AQWA

The wave, wind and current directions are defined in AQWA

as the directions which they are travelling towards.

The direction is defined as the angle between the wave (orcurrent, wind) and the positive x axis measured anti-clockwise.

Directions in AQWA are input and output in degrees.

X axis

Wave direction (or current, wind)

positive angle

Y



Phase Angle

In AQWA, the phase angle ( in degrees) of aparameter defines the time difference (dt) from thetime when the wave crest is at the CoG of thestructure to the time when the parameter reaches its

peak value. (dt= *T/360, where T is the waveperiod).

A positive phase angle indicates that the parameter

lags behind the wave.


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Waves in AQWA

Wave Types:

1) Airy Waves (linear wave)

a = A cos (-t + kx)

(: frequency in radians/sec; k: wave number)

Used in AQWA LINE, LIBRIUM, FER, DRIFT, NAUT(optional)

2) Stokes 2nd Order Wavesa = A cos (-t + kx) + 0.5 k A cos2(-t + kx)

Used in AQWA NAUT by default


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Waves in AQWA

Wave Forms:

1) Regular Waves

Used in AQWA LINE, NAUT (by default)

2) Irregular Waves

Defined by a wave spectrum and used in AQWALIBRIUM, FER, DRIFT, NAUT

Imported time history of wave elevation

used in AQWA DRIFT


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Waves in AQWA

Wave spectrum types accepted in AQWA are:

a. P-M spectrum

b. JONSWAP spectrum

c. User defined spectrumd. Gaussian spectrum for Cross Swell

Irregular waves can be in the form of:

a. Long crested waves; ORb. Short crested waves, ie a spread sea (only for AQWALIBRIUM and FER)


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Wind and current in AQWA

Wind types accepted in AQWA are:

a. Uniform windb. Ochi and Shin wind spectrumc.API wind spectrum

d. NPD wind spectrume. User-defined wind spectrum

Current types accepted in AQWA are:

a. Uniform currentb. Profiled current velocity


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Wave Forces on Structures

For Diffracting Structures (modelled with plate elements)

- Incident wave force (Froude-Krylov force): from thepressure in the undisturbed waves.

- Diffraction force: due to stationary structuredisturbing the incident waves.

- Radiation force: due to structures oscillation which

generates waves.

- Drift force (net force due to high order effect)


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hydrodynamic forces on structures(1) on Diffraction elements

Fluid force

HydrodynamicHydrostatic

Wave exciting force

Ambient pressure

(incident wave or

Froude-Krylov force)

Effect of structure

on waves

(Diffraction)

Radiation force due

to structure motion

In-phase

(Added Mass)

Out-of-phase

(Radiation

damping)

F() K.xMa().x C().x


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For Morison Structures (modelled with Morisonelements, eg TUBEs, DISCs)

- Morison force (including drag) calculated

using Morison equation.

hydrodynamic forces on structures(2) on Morison elements


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Morison Force

Equation for Morison force calculation

For slender cylindrical elements (D/


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AQWA LINE - Introduction

AQWA-LINE is a 3D diffraction and radiation analysis program

Frequency domain

Structures are described by a number of panels

Source distribution approach (boundary integration method)A source is place at the centre of each panel and then the program solves forthe source strengths, subject to the boundary conditions:no flow through the hullno flow through the sea-bed

a free surface condition

Surface mesh


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AQWA LINE - Features

Removal of irregular frequencies by auto-generated lid

Multi-body hydrodynamic interactions (lid to suppress standing waves)

Forward speed This enables the pressure and velocity to be found at any point

Second order forces Mean drift forces:

Far field momentum theory

Near field pressure-motion integration method

Full QTF matrix (difference & sum frequency components)

AQWA-LINE provides hydrodynamic coefficients for use in other programs in theAQWA suite


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Theory in AQWA LINE

Assumptions Ideal fluid, irrotational and incompressible small wave elevation

Governing equation for the velocity potential

Body boundary condition (Timman-Newman relations)

)(02 == V

jje

j

Umnin +=

)(r

),,0(/)]([),,(

,0/)]([),,(

),,(

,),,(

23654

321

654

321

nnUUxmmm

UUxmmm

nnn

nnn

s

s

=+=

=+=

=

=

rn

n

nr

n


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Theory in AQWA LINE

Linearized free surface condition

Sea bed boundary condition

Radiation conditionA physical condition to avoid mathematical ambiguity which couldresult in structure induced waves travelling in the wrong direction

watershallowforbedseadzatz

waterdeepforzwhen

)(0

0

==

=

02

=

gz

e


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Theory in AQWA LINE

Numerical method

Linear superposition of 1st order potential components

I for incident wave, d for diffracted wave,j =1,2,,6 for radiated wave in 6 degrees of freedom,xj: the structure motion for unit wave amplitude

Forward speed effect: Encounter frequency

: angle between incident wave and forward speed

,][ 6

1

tij

j jdI

eex

=++=

)cos1(

g

Ue =


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Theory in AQWA LINE

Incident wave potential for finite water depth d

in which k is the wave numberdefined by:

Solution for diffracted and radiated wave potentialsusing pulsating source distribution

)cosh(

)](cosh[ )sincos(

kd

eedzkige

tiyxikti

I

++ +=

)tanh(2 kdgk=

dszyxGzyx

bs

= ),,;,,(4

1),,(


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Theory in AQWA LINE

Greens function (finite depth water, frequency domain):

Database method used for efficient and accurate evaluation

Minimum input frequency (rad/s): d: water depth

)()(cosh)(cosh)(

(2

)()(cosh)(cosh)cosh()sinh(

)(

2

11

),,;,,(

022

)22

00

'

krJdkdzkdk

ki

drJdzddd

e

pv

RR

zyxG

d

+++

+

++

+

+

+=

dg/*05.0


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Theory in AQWA LINE

The source strength at each panel on the structure surfaceis assumed constant,

calculated by solving the body boundary condition:

For the diffraction potential, the induced normal velocity

at the structure surface should negate that due to incident potential;

For the radiation potentials, the induced normal velocities (in 6 degrees

of freedom) should be the same as those due to structure motion.

ds

n

zyxGzyx

n

zyx

bs

+=

),,;,,(

4

1),,(

2

1),,(


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Theory in AQWA LINE

Pressure and 1st order wave force calculationHydrodynamic pressure on each panel can be calculated

from the linearized Bernoulli equation:

1st order wave forces are obtained by integratingthe pressure over the mean wetted body surface.

Froude-Krylov and diffraction force

Added mass and damping

Restoring (hydrodynamic stiffness)

Special cases

dSx

UinF dIS ejej b))(()( +

+=

dS

x

UinCiM jS eieijeeijae b )()()(2

+=+

tgwp =)1(

dSwngK jbS iij =

mgdSwngKmgdSwngKbSbS

+== 42245115 ,


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Theory in AQWA LINE

Second order forces

Perturbation approach (: small number related to wave amplitude)

If the 1st order motion/potential/force in the form of

then the 2nd order force in

mean 2nd order force components ( )

...)(2

1 )2(2)1()0( +++=+= pppgZp t

...),,( )2(2)1()0( +++== XXXZYXX

Different freq. components

Sum freq. components

)cossin()(1

)1(tbtatF iiii

N

i

+==

]})cos[(])sin[(

])cos[(])sin[({)( 1 1

)2(

tfte

tdtctF

jiijjiij

jiijjiij

N

i

N

j

++++

+ == =

ji =

ii

N

i

dF =

=1

)2(


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2nd order mean drift force calculation

Far field solution (momentum conservation method):

SR: vertical cylindrical boundary surrounding the structurein the flow field with a large radius R,

: fluid volume surrounded by SR and the structure surface.

- More accurate- Horizontal force/moment only- Single structure only (or multi-bodies without hydrodynamic interaction)

SdpdSVVdtV

SdpdVdt

dF

RR

R

S

n

S

n

S

nstrc

=

=

)2(

Theory in AQWA LINE


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Theory in AQWA LINE

Near field solution(pressure/motion integration method):

WL: mean water line along the structure surface;Sb : mean structure wetted surface

- Force/moment in 6 degrees of freedom for each structure- Multi-body hydrodynamic interaction

..

22)2(

..).(

5.05.0

gs

bS

bSWLrstrc

XRMdSnt

X

dSndlngF

++

+=


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Theory in AQWA LINE

Full Quadratic Transfer Function (QTF) Components at both difference and sum frequencies Each with in-phase and out-of- phase parts

2-D plot of QTF(real)

AGS -> File ->openGraph -> Function/processing

-> Data processing -> Wave forces-> Full-coupled QTFs -> 2-D plot

CQTF card in Options on Deck 0

( ) ( )[ ] ( ) ( )[ ]{ }

( ) ( )[ ] ( ) ( )[ ]{ } ++++++

+++++=

= =

+

= =

+

N

i

N

jjijiijjijiij

N

i

N

jjijiijjijiij

tQtQ

tPtPtF

1 1

1 1

)2(

sinsin

coscos)(

jijiijP /),(

1 2 j . n

1

2

i

n

Diagonal: Mean drift force/unit wave of 2


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Theory in AQWA LINE

similar to above

potentialorder2nd..

Momentum..

onAccelerati).(

Bernoulli.

integralWaterline)cos(.

)2(

..

2

1

41

41)(

+

+

+

+

=

bS

jis

j

ibS

ji

bS

WLjijiij

dSn

t

XgRM

dSntX

dSn

dlngP

)(ijQ


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Theory in AQWA LINE

Equation of motion in AQWA LINE

The response X (RAO) of a structure in waves is calculatedby solving the equation of motionin the frequency domain for unit wave amplitude:

where Ms is structure massMa is added mass (frequency dependent)C is damping (frequency dependent)

K is hydrostatic stiffnessF is wave force (incident and diffracting forces).

)()(])())(([ 2 FXKCiMM as =++


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Fluid forces on structures

Fluid force

HydrodynamicHydrostatic

Wave exciting force

Ambient pressure

(incident wave or

Froude-Krylov force)

Effect of structure

on waves

(Diffraction)

Radiation force due

to structure motion

In-phase

(Added Mass)

Out-of-phase

(Radiation

damping)

F() K.xMa().x C().x= + +


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using ANSYS

Install ANSYS-AQWA interface(1) copy anstoaqwa.mac to C:\Program Files\Ansys Inc\v110\ANSYS\APDL(2) open C:\Program Files\Ansys Inc\v110\ANSYS\APDL\start110.ans,

insert *ABBR, AQWA, ANSTOAQWA

run ANSYS

Notes:(1) define geometry of wetand dry surface separately;Z-axis upwards;

(2) SHELL63 for surface mesh,PIPE59 for tube;

(3) check normal direction(blue: outside; pink: inside);

(4) Click AQWA to outputAQWA data file;

(5) COG and mass need to bemodified.

Modelling (1)


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Using AGS (with AL****.LIN fi le)

Notes on AL****.LIN fi le (seeAGS-Help for details):

(1) each station starts from lowest point at centre plane;(2) all x-coordinates should be the same on each station;(3) max. 50 points on each station, condense points at high surface change;(4) input stations (max. 100) from stern to bow,

only two stations are needed to define a parallel midbody section.

run AGS(1) double clickAGS icon on screen;(2) Plots Select Lines Plan File (in Lines Plan Mesh Generation window)

open to find the *.lin file to be opened;(3) Plot Lines (in Lines Plan Mesh Generation window) to show offset curves;(4) input two drafts; COG, mesh size (in Lines Plan Mesh Generation window) ,

then Generate Mesh;(5) File Save *.DAT (in Lines Plan Mesh Generation window)

to save the generated file.

Create model (Approx. Dimensions: 200x40x15, mesh size:6)Notes: PMAS values in Deck 4 may need to be modified (data\lines\altank.lin)

Modelling (2)


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AQWA File Names

EveryAQWA file name has three parts:

(1) file prefix (two characters) - a code to identify the programal LINEab LIBRIUMaf FERad DRIFT

an NAUTaw WAVE

(2) run identifier(up to six characters) - a name to identify the run

(3) file extension (three characters)to identify the type of file (eg, .dat)

Example: altank1.dat (input data), abtank1.lis (output list file)


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AQWA Global/User defined Systems

AQWA Global Coordinate System (FRA): the origin lies in the still water plane

the positive z axis is vertically upwards

Right handed

0

Z

XW.L.

x

z

a

COG

ZLWL(deck2)

ZCGE(deck7)

User Defined SystemRight handed,oxy plane shifts vertically from OXY of FRA

R St 1 2


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Run stages 1 2

Use the model generated by AGS Be aware of warning messages

Check al**.lis file (displacement, mass, stiffness) Check geometry throughAGS

Run Stages 1-2


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Check geometry through AGS

Zooming, Rotating, Shade, Showing diff panels, Numbering;

Command: omit element -> Plot (to omit all the elements)

select element 1 to 10 ->Plot (to display el#1-10 only)


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AQWA File Types

Each AQWA run involves several files.

The names of the files differ only in the file extension.

ASCII INPUT FILES.dat input data file (LBDNF)

.lin input file forAGS mesh generator

.msd input mass distribution for BM/SF (AGS)

.sfm input mass distribution for splitting forces (AGS)

.wht a wave height time history with IWHT in Deck 13 (D)

.wvt a wind velocity time history, no card needed (DN)

.xft an external force time history acting on a structure

no card needed (DN)

.mor mooring description file with FILE in Deck 14 (BDNF)


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AQWA File Types

INPUT/OUTPUT FILES (between stages).res restart file (binary, LBDNF)

.hyd hydrodynamics file (binary, L)

.eqp equilibrium position file (binary, B)

.uss source strength file (binary, with LDOP in Deck 0, L)

.pot potential file (binary, with LDOP in Deck 0, L)

OUTPUT FILES.mes output message file (ASCII, LBDNF)

.lis output listing file (ASCII, LBDNF)

.pos output position file (binary, DN)

.plt output graphic file (binary, LBDNF)

.pac pressures at centroids (binary, L)

.vac velocities at centroids (binary, L)

See AQWA-Ref 1.3 for details

I t D t ( d t) Fil


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Input Data (.dat) File

ASCII text file containing all the input data necessary forthe Stages of Analysis about to be executed.

in fixed format and must be entered using a text editor.

an editor that indicates the column & line no. of

the current cursor position is highly recommended.

Note: A graphical user interface, which allows interactive data input in a user-friendlyenvironment, is currently under development.


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AQWA-LINE Example Data File

Deck 0: overall

administration parameters

Deck 1: Node coordinates

* 999 for PMAS node

Deck 2: Element definitions

Analysis Stages

JOB MESH LINE

TITLE MESH FROM LINES PLANS/SCALING

OPTIONS REST ENDRESTART 1 2

*Deck 1 Coordinates --------------

01 COOR

01 1 45.000 -45.000 0.000

01 2 22.500 -45.000 0.000

. . .

01 511 146.000 0.000 0.000

. . .

END01 999 0.000 0.000 -10.620

*Deck 2 Element Definitions -------------

02 ELM1

02SYMX

02SYMY

02QPPL DIFF 0 (1)( 1)( 2)( 12)( 11)

. . . .02QPPL 0 (1)( 1)( 101)( 103)( 3)

. . . .

END02PMAS 0 (1)( 999)( 1)( 1)

02 FINI

Note: Symmetry card

(1) Save pre-processing time

(2) Save CPU time

(3) Enlarge capability

(4) But only for QPPL/TPPL


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*Deck 3 Material Properties - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

03 MATEEND03 1 3.32100E8

* Deck 4 Geometric Properties ---------------------------------------------------

04 GEOM

END04PMAS 1 3.6253E11 0.000000 0.000000 3.4199E11 0.000000 3.5991E11

* Deck 5 Global Data ------------------------------------------------------------

05 GLOB

05DPTH 250.0

05DENS 1025.0END05ACCG 9.806

* Deck 6 Wave Frequencies and Directions ----------------------------------------

06 FDR1

06FREQ 1 6 0.10472 0.15708 0.25133 0.41888 0.52360 0.59840

END06DIRN 1 3 0.00 45.00 90.00

* Deck 7 Analysis Position ------------------------------------------------------

07 WFS1END07ZCGE -10.6200

*------------------------------------------------------------------------------

08 NONE

* 1 2 3 4 5 6

*234567890123456789012345678901234567890123456789012345678901234567890

AQWA-LINE Example Data File (cont)

Deck 5: Defines the UNITSfor the analysis, seeApp. A

In degrees, ascending order

Deck 6: Analysis position


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Directions in AQWA

Directions must be input in ascending sequence (41 max.):

-180 to +180 degrees for a non-symmetric structure;

0 to 180 degrees for a structure symmetric about x axis (SYMX);

0 to 90 degrees for a structure symmetric about

both x and y axes (SYMX and SYMY).

y

x

v


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AQWA Data file format

JOB MESH LINETITLE MESH FROM LINES PLANS/SCALING

OPTIONS REST END

RESTART 1 2

4col 4col5 col5 col 10 cols 10 cols 10 cols

01 COOR

01 1 45.000 -45.000 0.000

END01 999 0.000 0.000 -10.620Column 21

02 ELM1

02QPPL DIFF 0(1)( 1)( 2)( 12)( 11)

06FREQ 1 6 0.10472 0.15708 0.25133 0.41888 0.52360

Note: Most input data should be typed into the required columns !!!SeeAQWA-Reference Chapter 4 for details


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Listing (.lis) File

ASCII text file containing most output data (in text form)

from the Stages of Analysis which have just been executed.

It can be examined using a text editor.

( )


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Restart (.res) File

This is a binary file,

written by all the AQWA programs,

contains database associated with all the Stages of

analysis which have so far been executed.

Examples:

If Stages 1 to 4 have been executed, it will contain:

(1) model definition(2) hydrodynamic database

(3) main analysis parameters

H d d i ( h d) Fil


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Hydrodynamic (.hyd) File

This is a binary file

created byAQWA-LINE after the diffraction / radiation analysis (Stage 3).

contains the hydrodynamic database from theAQWA-LINE run.

Comparison of AL**.RES and AL**.HYD (afterAQWA-LINE Stage 3)

restart file(RES) hydrodynamics file(HYD)

model definition

hydrodynamic database hydrodynamic database

further run further run

Used for AGS manipulate (ALDB in Deck 0,

regenerate .HYD file (RDDB) FILE in Deck 6 )

P iti Fil ( d )


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Position Files (.pos and .eqp)

Both are binary files.

AB***.eqp file: created by AQWA LIBRIUM stores the equilibrium positions of a system of structures.

can be read in by FDN as start position(with an option RDEP in Deck 0).

A****.pos file: created during a time domain analysis by DN

stores the positions, velocities, etc of a system of structuresfor every time step.

AGS Pl t Fil ( lt)


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AGS Plot File (.plt)

This is a binary file

created during a calculation stage (Stage 3 or 5)

contains either:

time history of forces and motions (DN) positions and forces during iteration

towards equilibrium (B) forces and responses as a function of

frequency (LF)

forAGS use

AQWA R t t St


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AQWA Restart Stages

Stages: Categorize analysis procedures

Can be run individually/in combination Data transfer through stages

Stage 1 Model Definition, Decks 1 to 5

Stage 2 Hydrodynamic Database, Decks 6 to 8

Stage 3 Diffraction/Radiation Analysis* (L)

Stage 4 Main Analysis Parameters Decks 9 to 20 (BDNF)

Stage 5 Main Analysis* (BFDN)

* Calculation Stages only

St 1


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Stage 1

Decks: Categorize input data

Deck 1 COOR Node Coordinates

Deck 2 ELM* Element Definitions

Deck 3 MATE Material Properties

Deck 4 GEOM Geometric Properties

Deck 5 GLOB Global Constants

Deck Header (compulsory)

Depth, G, (water): UNITS

Structure Number

St 2


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Stage 2

Deck 6 FDR* Regular Wave Definitions

(1) frequencies and directions(2) copy, merge, edit the existing hydrodynamic database.

Deck 7 WFS* Hydrodynamic Properties (wave freq. range)

Hydrostatic Properties (stiffness and buoyancy)

Analysis Position (ZCGE, can be replace by ZLWL in Deck2)

Deck 8 DRC* Drift Force Coefficients

* Structure Number

Note: The hydrodynamic properties input in Stage 2 are used to

modify or replace those calculated by AQWA-LINE (Stage 3)


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Stage 3

This is the main AQWA-LINE analysis and is a calculationstage only.

Note: The hydrodynamic properties input in Stage 2

are used to modify or replace those calculated

by AQWA-LINE (Stage 3)

Stage 4


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Stage 4

Deck 9 DRM* Drift Motion Parameters (drift freq.)

(drag, added mass/damping)

Deck 10 HLD* Hull Drag Coefficients(1) current/wind drag coefficients(2) external force by user_force.dll (with option FDLL)

Deck 11 ENVR Environmental Parameters (wind and current)

Deck 12 CONS Constraints (deactivate/constraint)

Deck 13 SPEC Spectral Parameters(wave, wind spectrum / time history)

WAVE Regular Wave Parameters (N)

Deck 14 MOOR Mooring Line Definitions(mooring, fender, pulley, winch)

* Structure Number

Stage 4 (cont)


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Stage 4 (cont)

Deck 15 STRT Starting Conditions (BFDN)

Deck 16 TINT Time Integration Parameters (D,N)

LMTS Iteration Parameters (B)

Deck 17 HYDC Additional Hydrodynamic Parameters for Tubes

(scaling & slamming factors , N)

Deck 18 PROP Printing Options (for additional information)

Deck 19/20 NONE Reserved for future use

St 5


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Stage 5

This is the main solution stage and is a calculation stage only.

Deck 21 ENLD Element and nodal loads

(on TUBEs, Stage 6, DN)

AQWA Element Types


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AQWA Element Types

Elements are defined in AQWA Deck 2:

QPPL : Quadrilateral panel (diffracting or non-diffracting)

TPPL : Triangular panel (diffracting or non-diffracting)

TUBE : Tube element (circular cross section)

STUB : Slender tube element (non-circular cross section allowed)PMAS: Point mass and inertia

PBOY: Point buoyancy

FPNT : Field point (for wave surface calculation)DISC : Circular disc with no thickness.

Notes:(1) DIFF is needed for diffracting QPPL and TPPL elements;

(2) ILID/VLID for defining external diffracting elements;

Definition of other elements


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Define TUBE element

See APP H

Define DISC elements

Program nameOB MESH NAUTTI TLE TUBES AND DI SCSOPTI ONS REST END

RESTART 1 501 COOR010001 10. 0 0. 000 2. 000010002 10. 0 0. 000 0. 000010003 10. 0 0. 000 - 3. 000

END01 999 0. 00 0. 000 - 0. 50002 ELM102TUBE ( 2) ( 1, 1) ( 2, 1) ( 1) ( 1)02DI SC ( 1) ( 3) ( 2) ( 3)02DI SC ( 1) ( 1) ( 2) ( 3)

END02PMAS ( 1) ( 999) ( 2) ( 2)03 MATE03 1 1. 00E- 6

END03 2 4025. 0004 GEOM

04TUBE 1 1. 00 0. 05 0. 0004CONT 0. 75 1. 0004DI SC 3 1. 2004CONT 1. 14 1. 00

END04PMAS 2 6000. 00 0. 00 0. 00 6000. 00 0. 0 4000. 00

05 GLOB05DPTH 500. 005DENS 1025. 0

END05ACCG 9. 806. . . . . .20 NONE

Warnings in AQWA-LINE


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g Q

General warnings

requirements reason

No. of elements 8000 diff. solution time

12000 totalNormals point out modelling convention

No gaps force balance

Facets cannot cut surface solution requirement

Dimensions < KR good practice



75/167


g Q

Stage #1 checks (Geometric properties)

Area ratio of adjacent elements < 3

Aspect ratio > ,(c=1, for QPPL; c=2.3, for TPPL)

Element centres at least onefacet radius apart

Shape factor (parameter for the regularity of panel)

< 0.2 warning

< 0.02 fatal error

Note: SeeAQWA-Course Appendix 3 for detail

Csidelongest

areaAR .

2

arearf



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g

Stage #2 checks (hydrodynamic)

Longest side < 1/7 wavelength

Fatal error if more than 5% fail

Distance above sea bed must be > 0.5.rf(use non-diffraction elements otherwise)

Warning if nodes not connected to anotherelement(for pressure contour, NPPP in Deck 0 overrides warning)

Minimum wave frequency (rad/s) > dg /*.050

AQWA-LINE run


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Run stages 1 - 3

use generated model (altank1.dat altank2.dat) add LDOP, GOON option, check mass and inertia moments discuss .dat file discuss .lis file AGS to show results and functions

Useful Options in AQWA-LINE (1)


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p ( )

Following option cards can be used in Deck 0:

DATA check input data (equivalent to Stages 1-2, LBDFN)

GOON ignore non-fatal modelling rule violations (L)

REST define restart stages (LBDFN)

LDOP LOad OutPut - outputs .POT and .USS files needed for

pressure calculations (e.g pressure plots, SF/BM) (L)

PRCE PRint Card Echo for Decks 1 5 (LBDFN)PPEL Print Properties for each Element (LBDFN)

Useful Options in AQWA-LINE (2)


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p ( )

NPPP No Pressure Post-Processing - prevents nodalconnectivity warnings (L)

CRNM Re-calculate RAOs (LF)

NRNM Calculate nodal RAOs(L)

NQTF Use near-field solution for drift force coefficients (L)

CQTF Calculate QTF matrix (L)

AQWA-LINE Post Processing


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Wave surface contour plots

Note:

LDOP card in al*.dat file run AGS

(1) double-clickAGS icon on screen;(2) File Open to input al*.res file;(3) Plots to show the model;(4) Wave Contours to show or calculate wave contour if not existing;(5) choose required waves (dir. freq. in Wave Surface Contours window);(6) tick Cycle to animate;(7) point Cursorto a specified location to show the numerical value at that point.



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Air Gap

Note: LDOP card in al*.dat file run AGS

(1) double-clickAGS icon on screen;(2) File Open to input al*.res file;(3) Plots to show the model;

(4) Wave Contours to show or calculate wave contour if not existing;(5) choose required waves (dir. freq. amp. in Wave Surface Contours window);(6) RAO Motion Ref. Height(Z) above SWL Include RAO motion;(7) tick Cycle to animate;(8) point Cursorto a specified location to show the numerical value at that point.



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Pressure Contours

Note:

run AGS

(1) double-clickAGS icon on screen;(2) File Open to input al*.res file;

(3) Plots to show the model;(4) Select (in Model Visualization window) Pressure Contours;

(5) choose required waves (dir. freq. in Pressure Contours window) Time=t to animate;(6) Select (in Model Visualization window) Sequence

(7) Start Sequence (in Define Sequence window) Stop Sequence Record Every save sequence files if required

(8) Hardcopy Output .bmp on playback Rewind BMP FILE DUMP (yes)

(9) Using a software to convert .BMP file into .gif file which may be replayed by internetexplorer or .avi file which can be insert into Powerpoint



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AQWA LINE Post Processing

Diffracted Wave Surface

Note:

LDOP card in al*.dat file run AGS

(1) double-clickAGS icon on screen;(2) File Open to input al*.res file;(3) Plots to show the model;

(4) Select (in Model Visualization window) Pressure Contours;(5) choose required waves (dir. freq. in Pressure Contours window) Time=t to animate;(6) View Angle (in Pressure Contours window) Choose view angle (in Contour View Angle window)(7) Option (in Pressure Contours window) Wave Amplitude & Diffracted Wave Surface

(in Hull Contours / Diffracted Wave Option window);(8) Select (in Model Visualization window) Sequence(9) Start Sequence (in Define Sequence window) Stop Sequence Record Every

AQWA Database Manipulation


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Structure number inALTANK2

Reason: without re-running the full AQWA-LINE analysis,

add in additional nodes, elements, damping etc;

combine several databases into one.

Example 1: modify nodes & elements of single structure

(1) copy existing data file ALTANK2.DAT to ALTANK3.DAT;(2) add new nodes, (non-diffracting) elements

(3) delete all wave frequency and direction cards in Deck 6,

change this deck into:06 FDR1

06FI LE ALTANK2. HYD06CSTR 1

END06CPDB

(4) runAQWA-LINE for ALTANK3.DAT (which takes a few seconds).



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(cont.1)

New card to add damping

Columns 51-60 for rolldamping

Structure number in AL1

Structure number in AL2

Example 2: modify damping of single structure

(1) copy existing data file ALTANK3.DAT to ALTANK4.DAT;(2) delete all wave frequency and direction cards in Deck 6,

change this deck into:

06 FDR1

06FI LE ALTANK2. HYD06CSTR 1END06CPDB

(3) add new damping coefficients(CRNM option needed for RAO recalculation);

07 WFS1

07ZCGE 0. 0000END07FI DD 1. 000E09

(4) runAQWA-LINE for ALTANK4.DAT (which takes a few seconds).

Compare the RAOs in ALTANK3 and ALTANK4 usingAGS (merging curves)


(cont 2)


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(cont.2)

Multiple structure database combination

(1) merging without hydrodynamic interaction

run each model (AL**1.dat and AL**2) individually;

include all structure definitions in the new AL**3.DAT file

add corresponding file name in DECK 6 FILE card inAL**3.DAT for each structure

(2) modify nodes etc for hydrodynamic interaction model

Similar to Example 2, but in Deck 6 only the first structure needs to beinput for each interaction group.

NOTE: When CQTF is used, manipulation can been done in version 12.0 thereafter

AQWA LIBRIUM introduction


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Equilibrium position, Static and Dynamic stability

- Complex ship/ offshore structure system;- Various mooring, fender, pulley, winch, constraints

configuration;- Equilibrium estimation underwave, wind and current

combination;- Database approach for static catenary mooring line;- Finite element approach for dynamic cable (drag force);- Iteration approach for determining equilibrium position;- Calculate the eigenvalues of linearised stiffness matrix

to obtain static stability;- Eigenvalues of the impedance matrix to give dynamic

stability.- Series of wave spectrums and mooring configurations

Theory in AQWA LIBRIUM


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Equation for determining static equilibrium position:

K is the stiffness matrix of the system,F is the force matrix.

The program iterates until X=|Xj+1-Xj| is less than a defined tolerance

Static stability

Eigenvalue (0, stable)

Dynamic stability

Eigenvalue (f0 and g=0, unstable; f>0 and g0, fishtailing)

),,0from(

,0

igfeXXXX

X

X

X

X

t +===++

=

+

KCM

0I

KMCM 11

0= XX K

)()(11 jjjj XFXXX + += K

Analysis Procedure


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y

Input in RESTART cardstarting from Column 21

A common method of analysis

(1) run Stages 1 to 3 in AQWA-LINE

(2) run Stages 4 to 5 in another program, say, AQWA-LIBRIUM.

Example:

Step 1: AQWA-LINE run Step 2:AQWA-LIBRIUM run

(Restart 1 to 3) (Restart 4 to 5)

Input Files Output Files Input Files Output Files

altest.dat altest.lis abtest.dat abtest.lis

altest.res altest.res abtest.resaltest.hyd abtest.eqpaltest.plt

Analysis Procedure (cont)


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Stage 4 in AQWA-LIBRIUM

model definition restart file

hydrodynamic database restart file

main analysis parameters input data file

Note: Decks 1 to 8 data is read from the restart file

Decks 9 to 20 are required in the input data file

(Decks 1 to 8 must be omitted if restart from Stage 4).

Stage 5 in AQWA-LIBRIUM (Main analysis, no extra input)

AQWA-LIBRIUM (Example 1)


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JOB card

Read database

Deck 9: drift motion parameters;Deck 10: wind and current drag; Deck 12: constraints;Deck 11: environment; Deck 13: spectrum

Deck 14: Mooring systemNB new nodes needed

Deck 15: Initial position of COG in global frame

J OB TEST LI BRTI TLE FALTI NSEN BOX - MODEL 1

OPTI ONS REST ENDRESTART 4 5 ALBOXM09 NONE10 NONE11 NONE12 NONE13 SPEC13SPDN 315. 0

END13PSMZ 0. 300 2. 000 4. 000 8. 00014 MOOR14LI NE 1 501 0 511 1. 4715E6 100. 014LI NE 1 502 0 512 1. 4715E6 100. 014LI NE 1 503 0 513 1. 4715E6 100. 0

END14LI NE 1 504 0 514 1. 4715E6 100. 015 STRT

END15POS1 1 1 0. 0 0. 0 1. 5 0. 0 0. 016 NONE17 NONE18 NONE19 NONE20 NONE

Drag in AQWA (deck 10)


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(1) Current and Wind Force Coefficients

DIRN Dir1 DirN 1 . N (optional)SYMX (optional)

CUFX Dir1 DirN C1 . CN

WIFX Dir1 DirN C1 . CN

etc

Dir: direction number directions default to LINE wave directions;

C1: Drag Force Coefficients

For relative current velocity V in directionforce in X direction = CUFX.V

2

force in Y direction = CUFY.V2

yaw moment = CURZ.V2

Direction sequence no.IfDIRN is not present in Deck 10,the directions are those defined

on the DIRN cards in Deck 6

Drag in AQWA (deck 10)(cont 1)


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(cont 1)

(2) Morison Drag Coefficients (for ship hul l)

MDIN Nrow Ncol C1 . C6

Nrow: Row number in drag matrix

Ncol: Column number in drag matrix

C1 C6: Drag Force Coefficients

=

.

.

.

.

.

.

.

666564636261

565554535251

464544434241

363534333231

262524232221

161514131211

zz

yy

xx

CCCCCC

CCCCCC

CCCCCC

CCCCCC

CCCCCC

CCCCCC

DragForce

Useful options in AQWA LIBRIUM


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STAT STATic stability only

DYNA DYNAmic stability only

PBIS Print Both Iteration Steps (prints full results at each step)

PRAF Print all freedoms (in spite of DACF cards on DECK12)

In JOB card Deck 0

In OPTIONS card Deck 0

AQWA-LIBRIUM Example 2 (ABTANK4)


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JOB TANK LIBR

TITLE SINGLE TANKER WITH MOORING

OPTIONS REST PBIS END

RESTART 4 5 ALTANK4

09 NONE

10 HLD1

10SYMX

10DIRN 1 5 0.0 20.00 40.00 60.0 80.00

10DIRN 6 10 100.00 120.00 140.00 160.0 180.00

10WIFX 1 5 1.460E3 1.692E3 1.685E3 1.175E3 3.745E2

10WIFX 6 10 -3.427E2 -9.839E2 -1.520E3 -1.692E3 -1.794E3

10CUFX 1 5 0.505E5 0.572E5 0.532E5 0.344E5 0.172E5

. . .

END10CURZ 6 10 0.808E7 0.220E8 0.191E8 0.103E8 0.00000

JOB card

Read database

Direction sequence no.If DIRN is not present in Deck 10, the directions

are those defined on the DIRN cards in Deck 6



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11 NONE12 NONE13 SPEC13SPDN 315.013CURR 1.00 315.013WIND 25.00 315.0

END13PSMZ 0.3000 2.0000 4.000 8.000

Deck 11:envirn.; Deck 12:constraints; Deck13: spectrum



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14 MOOR

14LINE 1 5001 0 6001 1.50E6 142.014LINE 1 5002 0 6002 1.50E6 142.014LINE 1 5003 0 6003 1.50E6 142.014LINE 1 5004 0 6004 1.50E6 142.0

END1415 STRT15POS1 100.00 0.000 0.000 0.000 0.000 0.000

END16 LMTS

END16MXNI 20017 NONE18 NONE19 NONE20 NONE

Deck 14: Mooring system

Deck 16: Iterative parameters

Deck 15: Initial position

AGS online calculation


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Mini-Librium

Note:

run AGS

(1) double-clickAGS icon on screen;(2) File Open to input al*.res file;(3) Plots to show the model;(4) Move Structure (in Model Visualization window) if needed;(5) MINI-LIBRIUM (in Model Visualization window);(6) Iterations (in MINI-LIBRIUM window to choose the iteration step number);(7) Equilibrate (till converged)

AGS online calculation


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Static stability

Note:run AGS

(1) Double-clickAGS icon on screen;(2) File Open to input al*.res file;(3) Plots to show the model;(4) Run ->AQWA-LIBRIUM(5) Display (inAQWA-LIBRIUM Run Monitorwindow) -> Static Stability Modes;(6) Click Mode# (in Static Stability Displacement Modes window to animate the mode).

Mooring Lines in AQWA (deck 14)


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Mooring lines can be defined in (BDNF)

Commonly used mooring types:

(1) LINE: Linear elastic line (weightless)

14LINE Ns1 Nd1 Ns2 Nd2 K L

(Ns1, Ns2: structure numbers; Nd1, Nd2: node numbers;K: stiffness; L: unstretched length)

(2) POLY: Polynomial elastic line (weightless)

14POLY K1 K2 K3 K4 K5

14NLIN Ns1 Nd1 Ns2 Nd2 (Ts) L (Fw) (Fp)

(K1, .., K5: stiffness;

Ts: winch tension; Fw: winch winding in friction factor;

Fp: winch paying out friction factor;Ts, Fw and Fp are only needed when the POLY line is used as a winch)


(cont.1)


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(cont.1)

Start from anchor point

(3) COMP/ECAT: Composite elastic catenary (with weight)

14COMP Nz Nx Ne Zmi n Zmax Sl ope

14ECAT M1 A1 EA1 Tmax1 L1



14NLI N Ns1 Nd1 Ns2 Nd2

Nz, Nx -- number of database points within z and x ranges.

Ne -- number of ECAT in this COMP line.

Zmin, Zmax -- Z range (measured from the anchor) for the attachment node.

Slope -- sea bed slope (in degrees; positive for slope going up from anchor towardsattachment point).

M1,M2,M3 -- mass per unit length for ECAT 1,2,3.

A1,A2,A3 -- equivalent cross section area.EA1,EA2,EA3-- Youngs modulus x area.

Tmax1-3 -- maximum tension.

L1,L2,L3 -- length of ECAT 1,2,3.

Ns,Nd -- structure number and node number (Ns1: fairlead structure).

Moorings database


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ZRMAX

ZRMIN

XRMIN XRMAX

Max. tension point

Slack point

AQWA-LIBRIUM Example 3


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JOB card

Stages 1-5, if Deck 1-8 include

Nodes for anchor points

J OB MESH LI BRTI TLE MESH FROM LI NES PLANS/ SCALI NG

OPTI ONS REST PBI S LSTF ENDRESTART 1 5

01 COOR015001 1700. 0. -300

015002 200. -1500. -300

015003 200. 1500. -300

015004 -1500. 0. -300

01 1 45. 000 - 45. 000 0. 00001 2 22. 500 - 45. 000 0. 000

01 3 0. 000 - 45. 000 0. 000. . .01 501 45. 000 0. 000 0. 00001 511 146. 000 0. 000 0. 000. . .

END01 999 0. 000 0. 000 - 10. 62002 ELM102SYMX02SYMY02QPPL DI FF 0 ( 1) ( 1) ( 2) ( 12) ( 11)02QPPL DI FF 0 ( 1) ( 11) ( 12) ( 22) ( 21)02QPPL DI FF 0 ( 1) ( 21) ( 22) ( 32) ( 31)02QPPL 0 ( 1) ( 1) ( 5) ( 105) ( 101). . . .

END02PMAS 0 ( 1) ( 999) ( 1) ( 1)02 FI NI

AQWA-LIBRIUM Example 3 (cont.)


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03 MATEEND03 1 3. 32100E8 0. 000000 0. 000000

04 GEOMEND04PMAS 1 3. 6253E11 0. 000000 0. 000000 3. 4199E11 0. 000000 3. 5991E11

05 GLOB05DPTH 250. 005DENS 1025. 0

END05ACCG 9. 80606 FDR1

06FILE ALBOXM.HYD

06CSTR 1

END06CPDB07 WFS107ZCGE - 2. 0000

END07FI DD 1. 000E0908 NONE09 DRM109FI DD 1. 0373E5 1. 5702E6 1. 0E07 4. 0E09 2. 0E10 5. 000E09

END0910 HLD1

10WI FX 1 5 1. 460E3 1. 692E3 1. 685E3 1. 175E3 3. 745E210WI FX 6 9 - 3. 427E2 - 9. 839E2 - 1. 520E3 - 1. 692E310WI FY 1 5 0. 000E0 1. 803E3 3. 623E3 5. 168E3 6. 093E310WI FY 6 9 6. 293E3 5. 618E3 4. 103E3 0. 010WI RZ 1 5 2. 475E2 - 1. 407E5 - 1. 689E5 - 1. 068E5 - 1. 167E410WI RZ 6 9 1. 167E5 1. 842E5 1. 559E5 0. 0

Read database from AQWA-LINE



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Composite catenary(start from anchor section)

Fairlead first, anchor point second

10CUFX 1 5 0. 505E5 0. 572E5 0. 532E5 0. 344E5 0. 172E510CUFX 6 9 - 0. 160E5 - 0. 295E5 - 0. 451E5 - 0. 466E5

10CUFY 1 5 0. 000E0 0. 207E6 0. 394E6 0. 486E6 0. 542E610CUFY 6 9 0. 550E6 0. 478E6 0. 382E6 0. 010CURZ 1 5 0. 000E0 - 0. 118E8 - 0. 213E8 - 0. 239E8 - 0. 118E8

END10CURZ 6 9 0. 808E7 0. 220E8 0. 191E8 0. 011 NONE12 NONE13 SPEC13SPDN 315. 013CURR 1. 00 315. 0

13WI ND 10. 00 315. 0END13PSMZ 0. 3000 2. 0000 4. 000 8. 00014 MOOR14COMP 20 30 3 280. 300.

14ECAT 150.00 0.00 6.0000E8 7.500E6 500.0

14ECAT 120.00 0.00 9.0000E8 7.500E6 500.0

14ECAT 170.00 0.00 6.0000E8 7.500E6 700.014NLI N 1 3201 0 500114NLI N 1 3201 0 5002

14NLI N 1 3201 0 5003END14NLI N 1 3201 0 5004

15 STRTEND15POS1 213. 000 - 213. 000 - 2. 00 0. 000 0. 000 144. 0



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Iteration controls

16 LMTS

16MXNI 25016MMVE 1 1.5 1.5 1.5 1.5 1.5 1.5

END16MERR 1 0.5 0.5 0.5 0.5 0.5 0.5

17 NONE18 NONE19 NONE20 NONE


(cont.2)


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( )

Similar to NLIN

Catenary hydrodynamic coefficient

AQWA Cable Dynamics (only applicable to COMP/ECAT): (abtank6)

14 MOOR14COMP 20 30 3 490. 510.14ECAT 150.00 0.010 6.0000E8 7.500E6 400.014ECAH 1.00 0.75 0.1014ECAT 120.00 0.010 9.0000E8 7.500E6 500.0

14ECAT 170.00 0.010 6.0000E8 7.500E6 700.014ECAH 1.00 1.00 0.1514NLID 1 5001 0 600114NLID 1 5002 0 600214NLID 1 5003 0 6003

END14NLID 1 5004 0 6004


(cont.3)


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( )

Fenders

14POLY K1 K2 K3 K4 K514FEND Si ze Kf Kc14FLIN Type Ns1 Nd1 Nd2 Ns2 Nd3 Nd4

in which

K1 K5 -- non-linear stiffness coefficientsSize -- uncompressed size of fender (normal direction)

Kf -- tangential friction coefficientKc -- normal damping coefficient

Type -- 1 = fixed fender, 2 = floating fenderNs1 -- Structure to which fender is nominally attached

Nd1, Nd2 -- Nodes defining attachment point and contact plane on 1st

structureNs2 -- Structure which fender contactsNd3, Nd4 -- Nodes defining attachment point and contact plane on 2nd structure

Note: Be aware of valid range of force extension/compression relationship

55

44

33

221 )()()()( XKXKXKXKXKT ++++=

Mooring Lines in AQWA (deck 14)(cont.4)


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With weight

(COMP/ECAT,NLIN,NLID)

Without weight

(LINE,NLIN, FEND/FLIN)

Other cards in deck 14 (refer to AQWA Reference Manual for more details)

BUOY/CLMP A buoy or clump weight

TELM: Tether element. (for installed or towed stiff tethers)

WNCH: Constant tension winch line

FORC: A constant force in a constant direction.

LINE/PULY: Linear elastic pulley line.

LE2D: User defined tension/extension data base.

SWIR: Steel wire with non-linear stiffness.

DWT0/LNDW A line winding in or out on a winch

LBRK: Line breaking.

FILE: Read in mooring definition from an external file *.MOR.

AQWA Printing Options (deck 18)


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by default, part of results output to limit file size

additional data can be output by Deck 18 commands

ALLM: Output the velocity, acceleration and position of a user specified nodedefined in the NODE card.

NODE: Output the motion of a user specified node

or the relative motion between two user specified nodes.

PREV: Write into *.LIS file every N time steps to reduce the size

PRNT: Print a force not in the output by default (See AQWA-ref 4.18.6)

PTEN: Output mooring tension, anchor uplift, laid length etc for mooring line.

ZRON: Output the z position of a node relative to the incident wave surface.

PMST: Output mooring sectional tensions for cable dynamic case

AQWA FER - introduction


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Principally for calculating the significant response

of amplitues in irregular waves.

Frequency domain program

Linearised stiffness matrix / damping to obtain the transfer function

and response spectrum

Simple, inexpensive approach to make systematic parameter study

Series ofwave spectrums and mooring configurations

Theory in AQWA FER


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Response spectrum in irregular waves

Sxixi(): response spectrum in i-th degree of freedom,Hij () : receptance matrix defined as:

Fj(): frequency dependent force(in j-th degree of freedom) on the structure

S(): the wave spectrum

)())]()(([mod)( 2 SFHS jijj

ixix =

12 ])())(([)( ++= KCiMMH asij

Linearisation in FER


113/167


Stiffness: stiffness (hydrostatic, mooring etc.) at the initial position,(= the static equilibrium position with RDEP option)

Damping:cable drag is linearised using the r.m.s. velocity, when NLID used

FD = (CD. |Vrms|) .V

wind drag is linearised,1st order hydrodynamic dampingany other input damping (fender, constraints)

Forces:

1st and 2nd order wave forces

Useful options in AQWA FER


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JOB options (JOB card)DRFT DRiFT frequency onlyWFRQ Wave FReQuency only

ANALYSIS options (OPTIONS card)

RDEP ReaD Equilibrium PositionFQTF Full diff freq. QTF to be used

Printing options (OPTIONS card)PRRI Printing RAOS at spectrum integration pointsGLAM Output significant motions in GLOBAL axis

AQWA-FER Example 1


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For AQWA-FER run

Read equilibrium position

from ABTANK6 database

J OB TANK FER

TI TLE SI NGLE TANKER WI TH CABLE DYNAMI COPTI ONS REST RDEP ENDRESTART 4 5 ABTANK6

09 DRM1*2345678901234567890123456789012345678901234567890123456789012345678901234567890

09FI DA 1. 0373E6 1. 5702E7 1. 0E12 1. 0E15 1. 0E15 2. 2564E1109FI DD 1. 80E5 1. 80E6 1. 0E10 1. 0E13 1. 0E13 1. 00E10

END0910 HLD1

10WI FX 1 5 1. 460E3 1. 692E3 1. 685E3 1. 175E3 3. 745E2. . .

10CURZ 1 5 0. 000E0 - 0. 118E8 - 0. 213E8 - 0. 239E8 - 0. 118E8END10CURZ 6 10 0. 808E7 0. 220E8 0. 191E8 0. 103E8 0. 00000

11 NONE12 NONE13 SPEC13SPDN 315. 013CURR 1. 00 315. 013WI ND 25. 00 315. 0

END13PSMZ 0. 3000 2. 0000 4. 000 8. 000

Optional freq. independent

added mass/damping

AQWA-FER Example (cont.)


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Not needed due to RDEP

14 MOOR14COMP 20 30 3 490. 510.

14ECAT 150. 00 0. 010 6. 0000E8 7. 500E6 400. 014ECAH 1. 00 1. 33 0. 1014ECAT 120. 00 0. 010 9. 0000E8 7. 500E6 500. 014ECAT 170. 00 0. 010 6. 0000E8 7. 500E6 700. 014NLI D 1 5001 0 600114NLI D 1 5002 0 600214NLI D 1 5003 0 6003

END14NLI D 1 5004 0 600415 NONE

* 15 STRT* 15POS1 100. 00 0. 000 0. 000 0. 000 0. 000 0. 000*END

16 NONE17 NONE18 NONE19 NONE20 NONE

AQWA NAUT & DRIFT - introduction


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AQWA-NAUT and DRIFT are time-domain simulationprograms

For a series of time-steps they:

calculate the total force on the structurecalculate the accelerationfind the new position of the structurerepeat

A two stage predictor/correctorintegration scheme is used

Theory in AQWA NAUT and DRIFT


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Equation of motion in time domain

F(t): the total force on the structure, including incident wave force diffraction force

mooring force drift force drag force constraint force, etc radiation force

Convolution integration form:

)()(..

tFtXMs =

)()()()()()]([ 10

tFdXttXtXt

as = +++ hKMM

Simulation of Irregular Waves


119/167


Wave spectrum treatment:

split into N sections of equal area define N wavelets with frequency at the centroid of the section

(max.200). the wavelets are added together with random phase angles

.

Wavelet: equal areas

S()

iii

N

iiiiii Satykxkatyx = ++=

=)(2),sincoscos(),,(

1

Comparison of DRIFT v. NAUT


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AQWA-DRIFT AQWA-NAUT

Irregular waves only Regular or Irregularwaves

Linearhydrostatic stiffness Non-linearhydrostatics /

Froude-Krylov force

2nd orderdrift coefficients 2nd orderincident wave

Omits drift forces(but some 2nd order effects)

Mean wetted surface Instantaneous wetted surface

AQWA-DRIFT Example 1


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Job card for DRIFT run

Drift & wave freq. motions

Print at both integration

stages.

Convolution method

for radiation force

J OB TANK DRI F WFRQTI TLE SI NGLE TANKER WI TH CABLE DYNAMI C

OPTI ONS REST PBI S CONV RDEP ENDRESTART 4 5 ABTANK6

09 DRM1*2345678901234567890123456789012345678901234567890123456789012345678901234567890

09FI DA 1. 0373E6 1. 5702E7 1. 0E12 1. 0E15 1. 0E15 2. 2564E1109FI DD 1. 80E5 1. 80E6 1. 0E10 1. 0E13 1. 0E13 1. 00E10

END0910 HLD110WI FX 1 5 1. 460E3 1. 692E3 1. 685E3 1. 175E3 3. 745E2

. . .

END10CURZ 6 10 0. 808E7 0. 220E8 0. 191E8 0. 103E8 0. 0000011 NONE12 NONE13 SPEC13SPDN 315. 013CURR 1. 00 315. 0

13WI ND 25. 00 315. 0END13PSMZ 0. 3000 2. 0000 4. 000 8. 000

AQWA-DRIFT Example (cont.)


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Define no. and value of time steps

Define printing options

14 MOOR

14COMP 20 30 3 490. 510.14ECAT 150. 00 0. 010 6. 0000E8 7. 500E6 400. 014ECAH 1. 00 1. 33 0. 1014ECAT 120. 00 0. 010 9. 0000E8 7. 500E6 500. 014ECAT 170. 00 0. 010 6. 0000E8 7. 500E6 700. 014NLI D 1 5001 0 600114NLI D 1 5002 0 600214NLI D 1 5003 0 6003

END14NLI D 1 5004 0 6004

15 NONE16 TI NT

END16TI ME 2000 0. 517 NONE18 PROP

END18PREV 519 NONE20 NONE

Useful options in AQWA DRIFT


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WFRQ Include Wave FReQency (default is Drift frequency only)

CONV Use CONVolution

PBIS Print Both Integration Steps

RDEP ReaD Equilibrium Position

FQTF Use diff freq. full QTF matrix (CQTF should be in LINE)

AQWA-NAUT Example 1


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Job card for NAUT run

Default regular waveanalysis

J OB MESH NAUTTI TLE MESH FROM LI NES PLANS/ SCALI NGOPTI ONS REST PBI S END

RESTART 1 501 COOR015001 1700. 0. - 30001 101 0. 001 0. 000 0. 000. . . .

END01 999 88. 025 0. 000 10. 00002 ELM102SYMX02QPPL DI FF 1 ( 1) ( 202) ( 201) ( 101) ( 102). . . .

END02PMAS 0 ( 1) ( 999) ( 1) ( 1)02 FI NI03 MATE

END03 1 84062048.04 GEOM

END04PMAS 1 1. 6812E10 0. 000000 0. 000000 3. 7659E11 0. 000000 3. 7659E1105 GLOB

05DPTH 1000. 005DENS 1024. 4END05ACCG 9. 807

AQWA-NAUT Example 1 (cont.)


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Copy AQWA-LINE database

Regular wave parameters

06 FDR1

06FI LE AL**** **. HYD06CSTR 1

END06CPDB

07 WFS107ZCGE - 2. 0000

END07FI DD 9. 986E0808 NONE09 DRM109FI DD 1. 0373E5 1. 5702E6 1. 0E07 4. 0E09 2. 0E10 5. 000E09

END0910 HLD110WI FX 1 5 1. 460E3 1. 692E3 1. 685E3 1. 175E3 3. 745E2. . . .

END10CURZ 6 9 0. 808E7 0. 220E8 0. 191E8 0. 011 NONE12 NONE13 WAVE13WAMP 12. 0

13WVDN 135. 0END13PERD 12. 00

AQWA-NAUT Example 1 (cont.)


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14 MOOR14COMP 20 30 3 280. 300.14ECAT 150. 00 0. 00 6. 0000E8 7. 500E6 500. 0

14ECAT 120. 00 0. 00 9. 0000E8 7. 500E6 500. 014ECAT 170. 00 0. 00 6. 0000E8 7. 500E6 700. 014NLI N 1 3201 0 500114NLI N 1 3201 0 500214NLI N 1 3201 0 5003

END14NLI N 1 3201 0 500415 STRT

END15POS1 213. 000 - 213. 000 - 2. 00 0. 000 0. 000 144. 016 TI NT

END16TI ME 2000 1. 017 NONE18 NONE19 NONE20 NONE

AQWA-NAUT Example 2


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J OB TANK NAUT I RRETI TLE SI NGLE TANKER WI TH CABLE DYNAMI COPTI ONS REST PBI S CONV RDEP ENDRESTART 4 5 ABTANK6

09 DRM1. . .

13 SPEC13SPDN 315. 0

13CURR 1. 00 315. 013WI ND 25. 00 315. 0

END13PSMZ 0. 3000 2. 0000 4. 000 8. 000. . .

16 TI NTEND16TI ME 2000 0. 5

17 NONE18 PROP

END18PREV 519 NONE20 NONE

Job card for NAUT run

Irregular wave analysis

CONV mandatory

Useful options in AQWA NAUT


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IRRE IRREgular wave analysis (CONV mandatory)

CONV Use CONVolution

LSTF Linear STiFness. Uses hydrostatic stiffnessfrom LINE without modification.

RDEP ReaD Equilibrium Position

Multiple structures (1)

without hydrodynamic interaction


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Wave,wind,

current

directions

Multiple Structures (1)without hydrodynamic interaction


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Node definition:

One set of nodes can be used.ELM1 and ELM2 use different node numbersto define the elements.

This can be inconvenient.E.g. if two models are created from .lin files in theAGS,both will have node number starting at 101.

STRC card in Deck 1

allows the same node numbers to be used for different models.

AQWA-LINE (AL2TANK1)


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Node definition for structure 1

JOB MESH LINE

TITLE TWO TANKER WITHOUT HYDRODYNAMIC INTERACTIONOPTIONS REST LDOP NQTF GOON END

RESTART 1 3

01 COOR

01STRC 1

01 1 0.000 0.000 5.000

. . . . .

01 999 110.552 0.000 15.000

* ATTACHMENT POINTS ON STRUCURE 1 FOR MOORING LINE BETWEEN ST#1-2015501 0.000 0.000 15.000

015502 230.000 0.000 27.000

01STRC 2

01 1 0.000 0.000 5.000

. . . .

. . . .

01 999 110.552 0.000 15.000

* ATTACHMENT POINT ON STRUCURE 2 FOR MOORING LINE BETWEEN ST#1-2

015501 0.000 0.000 15.000

015502 230.000 0.000 27.000

END01

Node definition for structure 2

AQWA-LINE (cont.)


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Element definit ion of ST#1

Material no. of ST#1

Geometry no. of ST#1

Material and geometry

definition of ST#1

02 ELM1

02SYMX

02QPPL DIFF 1 (1)( 101)( 1)( 6)( 102). . . . .

END02PMAS 0 (1)( 999)( 1)( 1)

02 ELM2

02SYMX

02QPPL DIFF 1 (1)( 101)( 1)( 6)( 102)

. . . . . .

END02PMAS 0 (1)( 999)( 2)( 2)

02 FINI

03 MATE

03 1 1.23009E8 0.000000 0.000000

END03 2 1.23009E8 0.000000 0.000000

04 GEOM

04PMAS 1 957.0E7 0.0 0.0 19050.0E7 0.0 19050.0E7

END04PMAS 2 957.0E7 0.0 0.0 19050.0E7 0.0 19050.0E7

AQWA-LINE (cont.)


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05 GLOB

05DPTH 500.005DENS 1024.4

END05ACCG 9.807

06 FDR1

06FILE ALTANK4.HYD

06CSTR 1

END06CPDB

06 FDR2

06FILE ALTANK4.HYD

06CSTR 1

END06CPDB

07 WFS1

07ZCGE 0.0000

END07FIDD 1.000E9

07 WFS2

07ZCGE 0.0000

END07FIDD 1.000E9

08 NONE

AQWA-LIBRIUM : Multiple structures(AB2TANK1)


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JOB TANK LIBR

TITLE TWO-TANKER WITHOUT HYDRO. INTER.

OPTIONS REST PBIS ENDRESTART 4 5 AL2TANK1

09 DRM1

09FIDA 1.0373E6 1.5702E7 1.0E12 1.0E15 1.0E15 2.2564E11

09FIDD 1.80E5 1.80E6 1.0E10 1.0E13 1.0E13 1.00E10

END09

09 FINI

10 HLD1

10WIFX 1 5 1.460E3 1.692E3 1.685E3 1.175E3 3.745E2

. . . . .

END10CURZ 6 10 0.808E7 0.220E8 0.191E8 0.103E8 0.00000

10 HLD2

10WIFX 1 5 1.460E3 1.692E3 1.685E3 1.175E3 3.745E2

. . . . .

END10CURZ 6 10 0.808E7 0.220E8 0.191E8 0.103E8 0.00000

FINI if no data for STR 2

AQWA-LIBRIUM (cont.)


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Mooring line between str#1-2

Initial position of COGs

Iterative control

. . . .14 MOOR

14COMP 20 30 3 490. 510.

14ECAT 150.00 0.010 6.0000E8 7.500E6 400.014ECAH 1.00 1.33 0.10

14ECAT 120.00 0.010 9.0000E8 7.500E6 500.0

14ECAT 170.00 0.010 6.0000E8 7.500E6 700.0

14NLIN 1 5001 0 6001

14NLIN 1 5002 0 6002

14NLIN 1 5003 0 6003

14NLIN 1 5004 0 6004

14LINE 1 5501 2 5501 1.50E7 100.0

END14LINE 1 5502 2 5502 1.50E7 100.015 STRT

15POS1 100.00 0.000 0.000 0.000 0.000 0.000

15POS2 -215.00 -000.00 0.000 0.000 0.000 0.00

END

16 LMTS

16MERR 0.05 0.05 0.05 0.1 0.1 0.2

16MMVE 2.00 2.00 0.5 1.0 1.0 2.0

END16MXNI 1200

17 NONE18 NONE

19 NONE

20 NONE

Use of FINI card


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Lots of occasions to use FINI card

Deck 2 (compulsory)

Multiple structures, not all of them defined in deck 6,7,8,9,10

End of deck

Multiple configurations of mooring lines (B/F),

insert FINI to separate two definitions of mooring systems

Multiple user defined wave spectrums (B/F),

insert FINI to separate each set of UDEF cards

Between two sections

AQWA-NAUT: Multiple structures(AN2TANK1)


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Read equilibrium position

JOB TANK NAUT IRRE

TITLE TWO-TANKER WITHOUT HYDRO. INTER.OPTIONS REST CONV RDEP END

RESTART 4 5 AB2TANK1

09 DRM1

09FIDA 1.0373E6 1.5702E7 1.0E12 1.0E15 1.0E15 2.2564E11

09FIDD 1.80E5 1.80E6 1.0E10 1.0E13 1.0E13 1.00E10

END09

09 DRM2

09FIDA 1.0373E6 1.5702E7 1.0E12 1.0E15 1.0E15 2.2564E11

09FIDD 1.80E5 1.80E6 1.0E10 1.0E13 1.0E13 1.00E10END09

10 HLD1

10WIFX 1 5 1.460E3 1.692E3 1.685E3 1.175E3 3.745E2

. . . .

END10CURZ 6 10 0.808E7 0.220E8 0.191E8 0.103E8 0.00000

10 HLD2

10WIFX 1 5 1.460E3 1.692E3 1.685E3 1.175E3 3.745E2

. . . .

END10CURZ 6 10 0.808E7 0.220E8 0.191E8 0.103E8 0.00000

AQWA-NAUT (cont.)


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Due to RDEP

Time step control

. . . .

13 SPEC13SPDN 315.0

13CURR 1.00 315.0

13WIND 25.00 315.0

END13PSMZ 0.3000 2.0000 4.000 8.000

14 MOOR

. . . . .

END14LINE 1 5501 2 5501 1.50E7 100.0

* 15 STRT

* 15POS1 100.00 0.000 0.000 0.000 0.000 0.000

* END15POS2 -215.00 -000.00 0.000 0.000 0.000 0.00

15 NONE

16 TINT

END16TIME 2000 0.5

. . . . .

20 NONE


with hydrodynamic interaction


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calculate hydrodynamic coefficients which take

full account of hydrodynamic interaction.

up to 20 interacting structures can be included.

AQWA-LINE (AL2TANK2)


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JOB MESH LINE

TITLE TWO TANKER WITH HYDRODYNAMIC INTERACTIONOPTIONS REST LDOP NQTF GOON END

RESTART 1 3

01 COOR

01STRC 1

*234567890123456789012345678901234567890123456789012345678901234567890

01 1 0.000 0.000 5.000

. . . . .

01 999 110.552 0.000 15.000* ATTACHMENT POINT ON STRUCURE 1 FOR MOORING LINE BETWEEN ST#1-2

015501 0.000 0.000 15.000

015502 230.000 0.000 27.000

01STRC 2

01 1 0.000 0.000 5.000

. . . .

01 999 110.552 0.000 15.000

* ATTACHMENT POINT ON STRUCURE 1 FOR MOORING LINE BETWEEN ST#1-2015501 0.000 0.000 15.000

015502 230.000 0.000 27.000

END01

Deck 0-1 similar to AL2TANK1.DAT

AQWA-LINE (cont.)

02 ELM1


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Remove geometric symmetry

Elements for attachment points.Needed when MSTR card used.

Move structure

Hydrodynamic interaction

Fictitious material and geometricproperties for attachment points

02 ELM1

02SYMX02QPPL DI FF 1 ( 1) ( 101) ( 1) ( 6) ( 102)

. . . . .02TPPL 45 ( 1) ( 4606) ( 4506) ( 4507)02RMXS02PMAS 0 ( 1) ( 999) ( 2) ( 2)02PMAS 0 ( 1) ( 5001) ( 3) ( 3)02PMAS 0 ( 1) ( 5002) ( 3) ( 3)02PMAS 0 ( 1) ( 5003) ( 3) ( 3)02PMAS 0 ( 1) ( 5004) ( 3) ( 3)02PMAS 0 ( 1) ( 5501) ( 3) ( 3)

02PMAS 0 ( 1) ( 5502) ( 3) ( 3)END02MSTR (999) (212.3182, -221.0850,5.5864)02 ELM202HYDI 1

. . . . . . . .

END02MSTR (999) (247.5926,-314.7867, 5.6123)

02 FI NI03 MATE03 1 1. 23009E8 0. 000000 0. 000000

03 2 1. 23009E8 0. 000000 0. 000000END03 3 1.00000E0 0.000000 0.000000

04 GEOM04PMAS 1 957. 0E7 0. 0 0. 0 19050. 0E7 0. 0 19050. 0E704PMAS 2 957. 0E7 0. 0 0. 0 19050. 0E7 0. 0 19050. 0E7

END04PMAS 3 1.0E0 0.0 0.0 0.0 0.0 0.0

AQWA-LINE (cont.)


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No symmetry,-180 to +180

Note: wave frequencies anddirections MUST be samefor hydro. interactingstructures

. . . .

06 FDR1

06FREQ 1 6 0. 10000 0. 20000 0. 30000 0. 40000 0. 50000 0. 6000006FREQ 7 11 0. 70000 0. 80000 0. 90000 1. 00000 1. 1000006DI RN 1 5 - 180. 00 - 160. 00 - 140. 00 - 120. 0 - 100. 0006DI RN 6 10 - 80. 00 - 60. 00 - 40. 00 - 20. 0 0. 0006DI RN 11 15 20. 00 40. 00 60. 00 80. 0 100. 00

END06DI RN 16 19 120. 00 140. 00 160. 00 180. 006 FDR206FREQ 1 6 0. 10000 0. 20000 0. 30000 0. 40000 0. 50000 0. 6000006FREQ 7 11 0. 70000 0. 80000 0. 90000 1. 00000 1. 10000

06DI RN 1 5 - 180. 00 - 160. 00 - 140. 00 - 120. 0 - 100. 0006DI RN 6 10 - 80. 00 - 60. 00 - 40. 00 - 20. 0 0. 0006DI RN 11 15 20. 00 40. 00 60. 00 80. 0 100. 00

END06DI RN 16 19 120. 00 140. 00 160. 00 180. 007 WFS107ZCGE 0. 0000

END07FI DD 1. 000E907 WFS207ZCGE 0. 0000

END07FI DD 1. 000E908 NONE


with hydrodynamic interaction


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The PFIX method (Deck 2)

Combine a floating and a fixed model into ONE structure

Put fixed part into a specified group

Use the PFIX card in Deck 2 to ground the fixed model

Symmetry


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SYMX means that AQWA can assume that the analysis issymmetric ABOUT THE FRA X-AXIS. This allows time-saving shortcuts to be used in the solution.

RMXS removes symmetry, creating a full model (even though themodel may still be a symmetric structure). It only applies to

T/QPPL elements, not to other elements or nodes.

MSTR moves the structure to a new definition position.

It only applies to elements and associated nodes, not to allnodes listed under the STRC card.

It actually moves the nodes and elements in the FRA.It is not the same as the POS card in Deck 15.

SYMY and RMYS have the same effect relative to the Y-axis

LIDS


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ILID to remove irregular frequencies inside structures

can be automatically generated VLID to reduce standing waves between structures

has to be defined by user

LIDS (cont)


146/167


ILID elements can be generated

automaticallyVLID elements must be defined in .dat

file

02 ELM1

02I LI D AUTO ( LI D_SI ZE=2. 0, START_NODE=5000)

02VLI D 777 ( DAMP=0. 01, GAP=8. 0)02SYMX02QPPL DI FF 1 ( 1) ( 101) ( 1) ( 6) ( 102). . . . .02PMAS 0 ( 1) ( 999) ( 2) ( 2)02MSTR ( 999) ( 212. 3182, - 221. 0850, 5. 5864)02QPPL DI FF 777 ( 1) ( 4606) ( 4506) ( 4507) ( 4508)02QPPL DI FF 777 ( 1) ( 4607) ( 4508) ( 4509) ( 4510). . . . .

END02 ELM202HYDI 1

. . . . . . . .

END02MSTR (999) (247.5926,-314.7867, 5.6123)

02 FI NI

Constraints in AQWA (deck 12)

1) O i i f M ti i U S ifi d D f F d (D O F)


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1) Omission of Motion in User Specified Degrees of Freedom (D.O.F)

DACF Ns Ndof

(Ns: structure number; Ndof : D.O.F. number), (PRAF may need)

2) Mechanical Articulations between Structures

Relative translational motion is not allowed, but relative rotationalmotion is possible.

DCON Nt Ns1 Nd1 (Nd3) Ns2 Nd2 (Nd4)

Nt: number of D.O.F. being locked by this constraint.

Nt=0: Ball and Socket, rotation in 3 D.O.F.

Nt=1: Universal joint, rotation in 2 D.O.F.

Nt=2: Hinge, rotation in 1 D.O.F.

Nt=3: Rigid connection, no rotation.

Ns1

Nd3Nd1, Nd2

Nd4

Ns2

Constraints in AQWA (example)


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Stinger model

1

constraints

Constraints in AQWA(example)

JOB MESH LIBR


149/167


JOB MESH LIBR

TITLE NORWAY SHIP + FLEXIBLE STINGER

OPTIONS REST GOON NPPP END

RESTART 1 5

01 COOR

STRC 1

1 115.000 0.000 0.000

....

* Nodes for third part of stringer

STRC 3

016001 0.000 -2.000 0.000

....

END016025 12.000 0.000 4.000

02 ELM1

02SYMX

02QPPL DIFF (43)( 1,7)( 2,7)( 9,7)( 8,7)

....

END02TUBE (1)( 6020)( 6017)(2)(2)

....

02 ELM3

02TUBE (1)( 6001)( 6002)(2)(2)

....

END02TUBE (1)( 6020)( 6017)(2)(2)

02 FINI

Constraints in AQWA(cont.)


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Constraint type:2 - hinged

Define a constraint

from St#1 to St#2

03 MATE

03 1 1.242E8

END03 2 7850.004 GEOM

04PMAS 1 957.0E7 0.0 0.0 19050.0E7 0.0 19050.0E7

04TUBE 2 0.500 0.050

END04TUBE 3 1.000 0.050

....

12 CONS

12DCON 2 1 6023 6020 2 6021 6004

END12DCON 2 2 6023 6020 3 6021 600413 NONE

14 MOOR

14LINE 1 5201 2 6025 5.0E05 25.0

END14LINE 2 6024 3 6022 5.0E05 0.0

....

20NONE

Definition of Tethers


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Tethers in a TLP Model

Two types: Towed and Installed;

Bending & lateral motion only;

Material defined in Deck 3 as flexible tube with Youngs modulus;

Small inline deformation defined by TSPV/TSPA cards.

Definition of Tethers (cont.)


152/167


JOB TETH NAUT

TITLE TETHERS

OPTIONS REST END

RESTART 4 5

09 NONE

. . . . . .

13 WAVE

13PERD 9.0

13WVDN 0.0

END13WAMP 8.0

14 MOOR

14TELM 300 301 2 2

14TELM 301 302 2 2

14TELM 302 303 2 2

14TSPV 0.0 5730.0 5730.0

14TSPA 0.0 5730.0 5730.0

14TETH 1 1 0 401

END14TETH 1 2 0 402

15 STRT

. . . . . .

Define tether elements;

Start from tail/anchor;

Min.2; max. 14/24

Material no.; see I.8.1.3

Geometry no.

Define tether lines

Sea bed, Node#401

Node#300

Vessel, Node#1

Node#303

Definition of Tethers (cont.)

hi h


153/167


I n whi ch:

TELM 300 301 2 2 -

def i nes a t et her el ement whi ch consi st sof t

Documents

aqwa-training-sxd-9