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Old   May 24, 2016, 10:31
Default FloatingObject parameter question
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Evan
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Hi, I'm trying to run a simulation of a 3x3x3 cube in a 100x100x20 environment using the framework of the floatingObject tutorial. I'm just unsure of what the 'innerDistance' and 'outerDistance' are. Here's my dynamicMeshDict file... thanks

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

dynamicFvMesh dynamicMotionSolverFvMesh;

motionSolverLibs ("libsixDoFRigidBodyMotion.so");

solver sixDoFRigidBodyMotion;

sixDoFRigidBodyMotionCoeffs
{
patches (floatingObject);
innerDistance 0.05;
outerDistance 0.35;


centreOfMass (50 50 10);

// Cuboid dimensions
Lx 3.0;
Ly 3.0;
Lz 3.0;

// Density of the solid
rho 920;

// Cuboid mass
mass #calc "$rho*$Lx*$Ly*$Lz";

// Cuboid moment of inertia about the centre of mass
momentOfInertia #codeStream
{
codeInclude
#{
#include "diagTensor.H"
#};

code
#{
scalar sqrLx = sqr($Lx);
scalar sqrLy = sqr($Ly);
scalar sqrLz = sqr($Lz);
os <<
$mass
*diagTensor(sqrLy + sqrLz, sqrLx + sqrLz, sqrLx + sqrLy)/12.0;
#};
};

report on;
accelerationRelaxation 0.7;
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Old   July 20, 2016, 16:38
Default innerDistance & outerDistance
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Gautami Erukulla
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Dear All,

I am simulating a 2D wave tank 15m long and 2m in height (OpenFOAM version 2.3.0). At the center of the wave tank there is floating object 0.5 m long and 0.4 m height, and its half immersed in water. The waves are generated at the inlet using the groovyBC velocity boundary condition. The floating object is provided 3 degree freedom (surge,heave and pitch). The simulation seems to be very sensitive to the innerDistance and outerDistance parameter in the dynamicMeshDict. Large displacements of the floating object distorts the surrounding mesh and crashes the run.
I do not seem to understand, how to set a good value for these parameters. I was hoping if any one could guide me with a good approximation for the innerDistance and outerDistance parameters. Thank you.

Most&More,
Gautama Erukulla.
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Old   October 20, 2016, 10:46
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Abigail Stehno
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  1. Anything within the innerDistance directly moves the mesh nodes as a rigid body.
  2. Between the innerDistance and outerDistance, the mesh nodes are morphed.
  3. Outside the outerDistance, no morphing occurs.
source : https://openfoamwiki.net/index.php/P...onSolverFvMesh
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