Oscillating Cylinder Dynamic mesh give "Negative Volume" error

  • Last Post 28 May 2020
cslong42 posted this 26 May 2020

Hello all,

I am trying to model an oscillating cylinder. When using dynamic mesh with 6dof I get the negative volume error. I am using 2019 R2 so I have been using the motion input under the boundary conditions and not using a UDF. My simulations will run with the BC input, but I do not see any movement of the cylinder in post. 

Setup: created fluid domain with the circle but out for cylinder. Inlet is 4D from cylinder, 4D above, and outlet is 10D down

Mesh: .0025m element size, named all sides

Setup: k-ep model, water is fluid, vel is 10m/s, cylinder motion set in BC with 10m/s and sinusoidal function in y direction, dynamic mesh described above.

Any help on fixing this issue would be appreciated.

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cslong42 posted this 26 May 2020

Kalyan Goparaju posted this 28 May 2020


If you are trying to model an oscillating cylinder, you will need to write a UDF that defines the motion of the cylinder, and attach it to the cylinder boundary through Rigid Body motion. This process does not require a 6DOF approach. Ensure smoothing and remeshing is turned on. Please see the tutorial at the link below for more details. 

Thank you,