Apply Boundary Condition to Nodes

Hello,

I imported a mesh from another software (node coordinates and connectivity) using the geometryFromMesh function.

However, Matlab broke the 3D geometry into some very strange faces, which makes applying boundary conditions to the faces very difficult.

Is there a way to give a list of nodes as a boundary condition to solve a PDE model?

Or, is there a way to assign faces to a 3D model based on surface nodes?

Thank You,

Vitaly

Answer 1

[KSSV]

Use this function https://in.mathworks.com/matlabcentral/fileexchange/32719-postprocessing-in-fem?focused=6861378&tab=function to plot mesh. You can extract the boundary nodes, but it depends on how your mesh is.

[Vitaly Kheyfets]

Thank You for your response. Although, I am not sure this answers my question. I would like to use the function: applyBoundaryCondition(model1,'face',face_upper,'u',0);

But instead of a face, I would like to give it an array of nodes. I know what nodes to give, I just need to figure out a way to assign them as the boundary condition.

Thanks,

Vitaly

[KSSV]

Are you using PDE tool box?

[Vitaly Kheyfets]

Yes I am. Is there a way to utilize the code you suggested to set a boundary condition using node coordinates? It looks like a post-processing code to identify surface nodes.

[Souvik Mukherjee]

Vitaly, I have the same problem as you. I know the boundary nodes, how can i apply boundary condition? For convenience lets just do Dirichlet. If you have solved this problem please let me know. Many thanks, Souvik

[Vitaly Kheyfets]

Hi Souvik,

Unfortunately, I ended up doing a work-around. Matlab has two major limitations: (1) it appears that boundary conditions can only be applied to geometry faces instead of directly on the mesh (which would be so easier) and (2) it kind of arbitrarily assigns face ids and it's hard to figure out what you're looking at.

Sorry couldn't be more help. If you figure out the answer, please let me know.

Thanks,

Vitaly

[Jide Kolade]

Vitaly, What was your work-around?

Jide