[quarkz]

Hi everyone, I read this interesting thread about having different motions with dynamicMesh.

For me, I am trying to simulate a wing with a rotating aileron (grid deformation) and doing a roll motion (entire grid rotates). Is this possible in OF?

I tried many ways and also tried to modify the relativeMotion tutorial. However, it just can't work. Moreover, I tried to use the solver solidBodyDisplacementLaplacian but OF complains that it can't find it. I wonder why.

[Steve Fu]

Hello Felix,
I also trying to do such a simulation case, the cylinder rotate and translate in the water domain by using tabulated6DoFMotion.
However, I failed many times.
Could you kindly share your case and ideas to me.
Thank you advanced.

[dntjudme]

Originally Posted by ConorMD

Hi everyone,

I have a similar task where I am using solidBody mesh movement and cell deformation. This time though, my cell deformation is happening within the solidbody. I am using a displacementLaplacian to model deflections on a rotating foil in a flow.

The problem I am having is that the displacementLaplacian is somehow shrinking the cellZone I am rotating to the point that the simulation fails (see image). The sim fails at the same point in time, regardless of the timestep size.

When the displacementLaplacian is disabled, the sim runs fine. So it appears the definition of my solidBody movement is ok. It appears to be in issue when combining the two solvers together.

Can anyone help me with this?
Thanks!

My dynamicMeshDict:

dynamicFvMesh  dynamicMotionSolverFvMesh;
motionSolverLibs ("libfvMotionSolvers.so");
solvers
(




	Turbine
	{
		motionSolverLibs ("libfvMotionSolvers.so");
		solver solidBody;

		solidBodyCoeffs
		{
   		 	cellZone        rotorVolume;
    			solidBodyMotionFunction  rotatingMotion;
    			rotatingMotionCoeffs
    			{
     			 origin		(0 0 0);
      			 axis		(0 -1 0);
     		 	 omega       5.625;
   			}
		}
	}

	Foil
	{
		motionSolverLibs ("libfvMotionSolvers.so");
		solver displacementLaplacian;
		//cellzone morphZone;
		

		displacementLaplacianCoeffs 
		{

   		diffusivity quadratic inverseDistance (foil1);

		}
	}

);

Hi Conor,

May I ask what version you are using?
I'm using .org version OpenFOAM v7, and it seems the dynamicMeshDict you have is not working on v7 version.

Thanks
Zs

[JunaidAhmad]

oversert domain edge node displacement.jpg


Hi,
Assalam O Aliqum,

I am running this freefall with inlet velocity simulation, and it run alright till it crash. I notice that in overset patch which is a cubic domain. the corners of this overset patch start displacing as you can see in fig above. the solid body whcih is wall is fine. Any solutions to this problem.


Stay Safe, Stay Happy

[JunaidAhmad]

Found the problem it was the inner and outer distance in dynamicMeshDict.
innerDistance 1e5; it was 0.3
outerDistance 1.1e5; it was 0.4






FoamFile
{
version 2.0;
format ascii;
class dictionary;
object dynamicMeshDict;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //

dynamicFvMesh dynamicOversetFvMesh;

motionSolverLibs (sixDoFRigidBodyMotion);

//cellZone oversetZone;

solver sixDoFRigidBodyMotion;

sixDoFRigidBodyMotionCoeffs
{

patches (solidBody);
innerDistance 1e5;
outerDistance 1.1e5;

centreOfMass (0.4 0.4 10.3);
//velocity (1 1 1);
g (0 0 -9.81);
// Cuboid dimensions
Lx 0.1;
Ly 0.1;
Lz 0.1;

// Density of the solid
rhoSolid 7800;
rho rhoInf;
rhoInf 1;

// Cuboid mass
mass #eval{ $rhoSolid*$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 0.9;
accelerationDamping 0.9;

solver
{
type Newmark;
}

// constraints
//{

/*
fixedPoint
{
sixDoFRigidBodyMotionConstraint point;
centreOfRotation (0.5 0.45 0.1);
}
*/

//fixedLine
// {
// sixDoFRigidBodyMotionConstraint line;
// //centreOfRotation (0.5 0.45 0.1);
// direction (0 0 1);
// }

/*
fixedAxis
{
sixDoFRigidBodyMotionConstraint axis;
axis (0 1 0);
}
*/
// }
}

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