Why do the laplacian mesh motion solvers solve for the cell centres?

tecmul · May 1, 2020, 00:56

In the displacementLaplacian and velocityLaplacian motion solvers, if I'm understanding the code correctly, the motion of the boundaries (provided by the user in the pointMotion file) is interpolated onto the centres of the boundary cells. Then the laplace equation equation is solved for the displacement/velocity of the cell centres. The new position of the mesh nodes is then interpolated from the cell centres. Is this correct? If it is, why not just directly solve for the displacements of the mesh nodes? Then you don't need to interpolate.

Michael@UW · May 4, 2020, 18:38

Foam-extend does that using FEM. FVM solves the variables at the celk center.

tecmul · May 4, 2020, 18:57

Quote:

Originally Posted by Michael@UW

Foam-extend does that using FEM. FVM solves the variables at the celk center.

That makes sense, thanks very much.

May 1, 2020, 00:56	Why do the laplacian mesh motion solvers solve for the cell centres?	#1
tecmul Member Join Date: Sep 2018 Posts: 53 Rep Power: 8	In the displacementLaplacian and velocityLaplacian motion solvers, if I'm understanding the code correctly, the motion of the boundaries (provided by the user in the pointMotion file) is interpolated onto the centres of the boundary cells. Then the laplace equation equation is solved for the displacement/velocity of the cell centres. The new position of the mesh nodes is then interpolated from the cell centres. Is this correct? If it is, why not just directly solve for the displacements of the mesh nodes? Then you don't need to interpolate.

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May 4, 2020, 18:38		#2
Michael@UW Senior Member Join Date: Jan 2019 Posts: 125 Blog Entries: 1 Rep Power: 0	Foam-extend does that using FEM. FVM solves the variables at the celk center.