Discussion Forum

My experience with the COMSOL FSI package is limited, so I would greatly appreciate any suggestions.

I would like to build an FSI model with two-way boundary coupling in which an elastic solid serves as an oscillating gate between the inlet and outlet of fluid flow. Ideally, the solid would start in the "closed" position, completely separating the inlet and outlet regions of flow. As pressure builds up, the gate should eventually be pushed open. Once open, it should then eventually return to the closed position as a result of the internal forces and Bernoulli effect (I'm assuming COMSOL takes this into consideration), again blocking all flow. The model would then ideally continue to oscillate between being open and closed in this matter. A colleague suggested that I would run into issues with this constantly deforming mesh - how would I account for this? Would I use a deformed mesh? Moving mesh?

Also, I saw the COMSOL FSI tutorial that modeled a closed gate valve (www.youtube.com/watch?v=FFjgFlwWdyc) by drastically increasing the viscosity within the gate region. A modification of this method could potentially work for my purposes since I could then keep the fluid mesh as one moving mesh piece that never breaks into two. However, the narrator in that tutorial stated that this method does not work for completely closed off flow systems (like mine). Does anyone know the reason for this?

Thank you for any insight into this problem.