[KevinMcTaggart]

I'm trying to compute forces on static bodies in uniform flow. I have created an initial case with a vertical cylinder. Unfortunately, the forces are very unrealistic, including negative drag force. Is Reef3D currently working for forces on bodies? Are there any problems with the attached input files? Is there a reason why I get wildly different forces when going from X 133 cylinder input to X 180 STL file input? I note that visualization suggests that the flow fields are generally correct, and that correct floating body volumes are given for X 133 and X 180. Surprisingly, 3 different sets of forces are written to console during each iteration, but no forces are written to file REEF3D_6DOF_forces_0.dat. Are the 3 different sets of console output forces due to the 3 different force methods (X 40 = 1, 2, and 3) being written?

[kamath]

Hi Kevin,
The force calculations should be working fine.
From your files, I would guess that the number of triangles used to represent the structure using X 133 and X 180 are different, which lead to different results.

You are probably better off going with X 180 stl input. Then you can ensure a larger number of triangles in the representation of the structure.

The three Xe/Ye/Ze.. outputs to the console are from the three RK3 steps.

I do get forces printed out to file, so unable to recreate that error.

Could you check if you have the latest RCs?