Learning Forum

[saherrer]

Hello all,

I have a an FSI case where I am trying to find the force applied to a thin shell membrane. Under normal wall boundary conditons, I can post process normally and find the total force by using reaction forces from .rst files and they generally align with the total drag from the fluent .dat files.

However, post processing this is quite a problem once I apply porous-jump conditions. The .rst files refuse to open at all, and the drag functions that normally work for wall conditions don't apply to a porous jump condition. I am trying my best to sum the x,y,z force components from the system coupling .case files, but I find that they do not match what the mechanical output file says is transferred between the two. I would really appreciate any help.

[KR]

Hello,

The porous jump is a special scenario where the force transferred does not include any viscous forces. The pressure drop obtained from the parameters such as thickness and coefficient defined at the porous jump condition is converted to a force vector, which is transferred via system coupling. 

If you wish to read further on this, I suggest you use the following link from the Fluent User's Guide (section 42.4.2. Force transferred to System Coupling from a Porous Jump Boundary)

42.4. Variables Available for System Coupling (ansys.com)

Karthik