Two way FSI negative cell volume in static analysis

sneaky · February 4, 2014, 01:46

Hey there,
I tried to set up a 2 way FSI for an elastic body with surrounding water flow. However, Fluent crashes because of negative cell volume. From my research, I know that decreasing the time step should help but since I am working with Static Structural and Steady Analysis in Fluent, there is no such thing as a time step. Are there any other things I could do?
I am using an unstructured Tet Mesh with inflation layers of the magnitude 10e-4m for a realizable k-epsilon model.

Thank you!
Steven

sneaky · February 8, 2014, 12:21

Is there really nobody who can help me?
I tried switching to transient as it is written that using smaller timesteps could improve the performance. Unfortunately, that does not change anything. I tried running the simulation with air instead of water and there were no errors. I guess that's due to the smaller deformation. However, I chose to remesh and smooth the tets in tet regions. Is there anything I should change additionally? I'm sure that I'm not the only one facing this kind of problem.

February 4, 2014, 01:46	Two way FSI negative cell volume in static analysis	#1
sneaky New Member Join Date: Feb 2014 Posts: 3 Rep Power: 12	Hey there, I tried to set up a 2 way FSI for an elastic body with surrounding water flow. However, Fluent crashes because of negative cell volume. From my research, I know that decreasing the time step should help but since I am working with Static Structural and Steady Analysis in Fluent, there is no such thing as a time step. Are there any other things I could do? I am using an unstructured Tet Mesh with inflation layers of the magnitude 10e-4m for a realizable k-epsilon model. Thank you! Steven

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February 8, 2014, 12:21		#2
sneaky New Member Join Date: Feb 2014 Posts: 3 Rep Power: 12	Is there really nobody who can help me? I tried switching to transient as it is written that using smaller timesteps could improve the performance. Unfortunately, that does not change anything. I tried running the simulation with air instead of water and there were no errors. I guess that's due to the smaller deformation. However, I chose to remesh and smooth the tets in tet regions. Is there anything I should change additionally? I'm sure that I'm not the only one facing this kind of problem.