Lobe Pump Analysis

asdR · March 18, 2015, 12:45

I am facing error in Mesh Motion in Fluent,

Warning : non-positive volumes exist.

Error: Update-Dynamic Mesh failed. Negative cell volume detected.
Error Object : #f

Another Problem is for what we locate POINT ON PLANE and PLANE NORMAL?

vasava · March 19, 2015, 08:35

To avoid the 'Negative Cell Volume' you can use a smaller time-step. Time-step small enough so that the distance covered is smaller than the size of the smallest element. You can also play around the dynamic mesh parameters to have a better mesh after each time step.

If you have selected the side faces as symmetry, you can just leave them for now.

asdR · March 20, 2015, 01:32

Sir the side faces are defined as DEFORMING MESH ZONES as PLANE.

I took time step size as 5e-4 and number of time steps as 1000.

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March 19, 2015, 08:35		#2
vasava Senior Member Paritosh Vasava Join Date: Oct 2012 Location: Lappeenranta, Finland Posts: 732 Rep Power: 22	To avoid the 'Negative Cell Volume' you can use a smaller time-step. Time-step small enough so that the distance covered is smaller than the size of the smallest element. You can also play around the dynamic mesh parameters to have a better mesh after each time step. If you have selected the side faces as symmetry, you can just leave them for now.

March 20, 2015, 01:32		#3
asdR New Member Arpit Join Date: Mar 2015 Posts: 3 Rep Power: 11	Sir the side faces are defined as DEFORMING MESH ZONES as PLANE. I took time step size as 5e-4 and number of time steps as 1000.