[Abderahmane]

Hello everyone, i hope you are OK and in a very good healthy.

Well, i have a question :
i use dynamic mesh & point displacement files to move an object, the idea is that i want to move some part of this object (only a partition of it) how can i do it ?


any answer or response is welcom

[Abderahmane]

does somebody knows how ? please !!

[Kojote]

For pointDisplacment

/*--------------------------------*- C++ -*----------------------------------*\
| ========= | |
| \\ / F ield | OpenFOAM: The Open Source CFD Toolbox |
| \\ / O peration | Version: 2.3.0 |
| \\ / A nd | Web: www.OpenFOAM.org |
| \\/ M anipulation | |
\*---------------------------------------------------------------------------*/
FoamFile
{
version 2.0;
format ascii;
class pointVectorField;
location "0";
object pointDisplacement;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
dimensions [0 1 0 0 0 0 0];
internalField uniform (0 0 0);
boundaryField
{
"(.*)"
{
type fixedValue;
value uniform (0 0 0);
}
"(wall|inlet)"
{
type oscillatingFixedValue;
refValue (0 0 0);
amplitude (0 0.0015 0);
frequency 2;
}
}

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

[Kojote]

/*--------------------------------*- C++ -*----------------------------------*\
| ========= | |
| \\ / F ield | OpenFOAM: The Open Source CFD Toolbox |
| \\ / O peration | Version: 2.3.0 |
| \\ / A nd | Web: www.OpenFOAM.org |
| \\/ M anipulation | |
\*---------------------------------------------------------------------------*/
FoamFile
{
version 2.0;
format ascii;
class dictionary;
location "constant";
object dynamicMeshDict;
}
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
dynamicFvMesh dynamicMotionSolverFvMesh;
solver displacementLaplacian;
diffusivity uniform;
displacementLaplacianCoeffs
{


diffusivity uniform;

//diffusivity directional (1 1e-6 1);

//diffusivity motionDirectional (1 1e-6 1);

// diffusivity file motionDiffusivity;

//diffusivity inverseDistance 1(floatingObjectBottom);

}
}
// ************************************************** *********************** //

[Kojote]

Hi

Is that what you needed?

Br

Christian

[Abderahmane]

Hello,

Thank you for your answer,


if i understand your files, your 'inlet' BC has a motion with a specified amplitude & frequency that's it ?


Well, my problem was not about moving an object. let's take for example a wing or an airfoil and i want to move only the trailing edge like 10 % of the chords in the trailing edge.

The airfoil is fixed but the trailing edge is vibrating did you get my point ?


thanks

[Kojote]

Hi,

then do a partition " trailing edge" of what you wanna move and move it only.

Br

Christian

[Abderahmane]

i had this idea, when i make the mesh i split the geometry, but imagine that when the geometry is splitted it may occur a discontinuity or both of the geomtries ( trailing edge and airfoil ) will be separated no ?

[vkid185]

Originally Posted by Abderahmane

i had this idea, when i make the mesh i split the geometry, but imagine that when the geometry is splitted it may occur a discontinuity or both of the geomtries ( trailing edge and airfoil ) will be separated no ?

Hi Marouf,

i'm working with a floating ship with rotating propeller and i think your problem is quite similar as in my case.

I also think that splitting the geometry into wing-part and trailingEdge-part is a right way of approaching. I suggest you should try define these 2 parts as a single body in the dynamicMeshDict, after that define informations about the moving of only the trailing edge in point Displacement.
Because my simulation is still crashed after running for several timesteps so this is just my though and i'm not sure if it works with your case.