Unexpected results with Version 23.08 floating body

KevinMcTaggart · September 1, 2023, 09:36

I've been getting very encouraging results for floating bodies using Version 23.03. For Version 23.08, results have given very unrealistic flows when using a floating body modelled with an STL file. I attach input files for a floating vertical cylinder.

valgrinda · September 10, 2023, 11:51

Thanks for the feedback and the very useful test case! There are two things that happened: There was still a problem with the boundary conditions of the turbulence model when used together with the 6DOF algorithm (fixed in newest RC). Previously, there was only one momentum option for 6DOF (low storage RK3). Now, all momentum schemes can be used together with 6DOF. In order to use the low storage RK3 scheme, N 40 4 needs to be selected.

Now, with the turbulence BC fixed, both N 40 3 and N 40 4 give very similar results.

September 10, 2023, 11:51		#2
valgrinda Super Moderator Hans Bihs Join Date: Jun 2009 Location: Trondheim, Norway Posts: 403 Rep Power: 19	Thanks for the feedback and the very useful test case! There are two things that happened: There was still a problem with the boundary conditions of the turbulence model when used together with the 6DOF algorithm (fixed in newest RC). Previously, there was only one momentum option for 6DOF (low storage RK3). Now, all momentum schemes can be used together with 6DOF. In order to use the low storage RK3 scheme, N 40 4 needs to be selected. Now, with the turbulence BC fixed, both N 40 3 and N 40 4 give very similar results. __________________ Hans Bihs Team REEF3D www.reef3d.com

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