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gibbogle
Sep28-09, 06:57 PM
We are trying to use COMSOL to model 2D flow in a simple geometry with a moving boundary, employing the ALE capability. The domain is rectangular, but a step front travels along one boundary.

-------------------------------------
| |
| |
| |
---- |
| -> |
| -> |
----------------------------------

(Please imagine that every last '|' on each line moved to the right and aligned to draw a vertical boundary line, and the last three lines are all displaced to the right. Somehow all the spaces I inserted have been collapsed.)

All boundaries except the right hand one are walls. The region is initially rectangular, and at the end of the simulation it is a thinner rectangle.

Because a moving boundary is handled by deforming the mesh, we are able to simulate a small amount of movement of the front, but then the mesh is deformed too much and the solution fails. Clearly we are pushing this feature beyond what it was designed to do.

I think what we really need to do is re-mesh at regular intervals (maybe every timestep). Is there a way to accomplish this in COMSOL? If not, what about ANSYS?

All suggestions gratefully received.

Cheers
Gib