Forces on Moving Boundaries

[ncalbrecht]

Hi,
first up thanks for the impressive software! I want to figure out, wether I can use FluidX3D to estimate the thrust of a propeller. I know, the current LBM implementation has issues with highly turbulent flow and needs very fine discretisation to avoid stairstepping, but I wanted to try what happens if I just crank up the mesh to sub mm size in water. However, as soon as I use moving boundaries for my propeller objects, the forces are always reported to 0. Force calculation for static objects works reasonable, but as soon as I add velocity during voxelisation it just reports 0. Is this intended behaviour or am I doing something wrong?

[ProjectPhysX]

I don't think this is possible with boundary forces directly. Better infer thrust force from generated flux (from velocity field) through an area behind the propeller.
Long answer here: #141 (comment)