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Rotational oscillations of 2D cube in water.

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Old   April 10, 2015, 10:37
Default Rotational oscillations of 2D cube in water.
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Alexander Lavrov
Join Date: Jun 2012
Location: Lisbon, Portugal
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I try to model roll (rotational oscillations) of 2D cube in water. I created the case. It is shown in attachment. I used tutorial slashingTank3D6DoF to create my case. The main original features are in the subroutines
pointMotionU
and
dynamicMeshDict
In the beginning I modelled heave and sway oscillation of the cube. It seems to me that the case is working for heave and sway without problems.
Array that dictates cube movement consists of 7 columns (time, displacement velocity in X, Y, Z directions, rotation velocity in X, Y, Z directions).
I cannot understand the dimension of the VALUE of rotational oscillation velocity. When I see the results in paraFoam it is obvious that if I increase the rotational velocity two times, the amplitude of rotational oscillations do not increase two times.
Dear forum participants. Thank you very much in advance for your help.
Alexander Lavrov, Lisbon, IST.
/*--------------------------------*- C++ -*----------------------------------*\
| ========= | |
| \\ / F ield | OpenFOAM: The Open Source CFD Toolbox |
| \\ / O peration | Version: 1.6 |
| \\ / A nd | Web: www.OpenFOAM.org |
| \\/ M anipulation | |
\*---------------------------------------------------------------------------*/
FoamFile
{
version 2.0;
format ascii;
class dictionary;
location "constant";
// object dynamicMeshDict;
object motionProperties; // old
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

dynamicFvMesh dynamicMotionSolverFvMesh;
motionSolverLibs ("libsixDoFRigidBodyMotion.so");
solver velocityLaplacian;

velocityLaplacianCoeffs
{
diffusivity inverseDistance (form);

}
// ************************************************** *********************** //
/*---------------------------------------------------------------------------*\
| ========= | |
| \\ / F ield | OpenFOAM: The Open Source CFD Toolbox |
| \\ / O peration | Version: 1.5 |
| \\ / A nd | Web: http://www.openfoam.org |
| \\/ M anipulation | |
\*---------------------------------------------------------------------------*/

FoamFile
{
version 2.0;
format ascii;
class pointVectorField;
object pointMotionU;
}

// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

dimensions [0 1 -1 0 0 0 0];

internalField uniform (0 0 0);

boundaryField
{
tank
{
type zeroGradient;
}

form
{
type solidBodyMotionDisplacement;
solidBodyMotionFunction tabulated6DoFMotion;
tabulated6DoFMotionCoeffs
{
CofG (600 0 0.25);
timeDataFileName "$FOAM_CASE/constant/150407_AMPL_10_4_PERIODS.txt";
}
}

atmosphere
{
type fixedValue;
value uniform (0 0 0);
}

front
{
type empty;
}
back
{
type empty;
}
}
// ************************************************** *********************** //
Attached Images
File Type: jpg 000.jpg (28.0 KB, 9 views)
File Type: jpg 001.jpg (29.2 KB, 7 views)
File Type: jpg 002.jpg (29.8 KB, 7 views)
Attached Files
File Type: zip 150409_CUBE_ROLL_80s_AMPL10_FORUM.zip (95.8 KB, 6 views)
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2d flow, dynamic mesh, roll motion, slashingtank

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