Moment of Inertia Issue
Hi, I am modeling an OWSC using open channel wave boundary condition and a dynamic mesh. Instead of using a UDF, I am using the built in 6DOF solver to assign rotation to the hinge of the OWSC. I am currently experiencing an issue with my OWSC model in Fluent 2021, similar to the issue found in this post:
The specific issue that I am having is this: whenever I start the simulation using dynamic mesh, the OWSC immediately “falls over” with high velocity. The mass of my device is around 300 kg, and the moment of inertia about the hinge is around 1500 kgm2 according to SolidWorks. After trying to isolate the issue, here is what I found: When I run the simulation with +1500 kgm2 as the moment of inertia, the OWSC immediately falls over counter-clockwise. When I run the simulation with -1500kgm2 as the moment of inertia, the OWSC immediately falls over clockwise. When I change the moment of inertia to some large value like 100,000 kgm2, the OWSC doesn’t fall over, and actually begins to act normally by oscillating back and forth as the waves hit it. However, a moment of inertia this large seems quite unrealistic..
The discussion link that I posted above seems to have been inconclusive, and didn't really help my case. I've tried reducing the time step, but nothing seems to be working.. Any ideas?