{"id":292617,"date":"2023-07-11T22:38:42","date_gmt":"2023-07-11T22:38:42","guid":{"rendered":"\/forum\/forums\/topic\/negative-cell-volume-occuring-when-using-a-quarter-model\/"},"modified":"2023-07-11T22:38:42","modified_gmt":"2023-07-11T22:38:42","slug":"negative-cell-volume-occuring-when-using-a-quarter-model","status":"closed","type":"topic","link":"https:\/\/innovationspace.ansys.com\/forum\/forums\/topic\/negative-cell-volume-occuring-when-using-a-quarter-model\/","title":{"rendered":"Negative cell volume occuring when using a quarter model"},"content":{"rendered":"

Dear fluent users,<\/p>\n

I have an entire model running well. Based on the reference paper, i need to mesh the model with mesh size of 10 µm which means more than 50 000 000 elements. I reduced the model to a quarter to save computational time but i have negative cell volume occuring during the simulation. I tried solutions provide on research gate for the same issue  :<\/p>\n

– try PISO method<\/p>\n

– Timesteps less than 0.005<\/p>\n

– reduce the relaxation energy value from 1.0 to 0.6<\/p>\n

but the issue still occurs.<\/p>\n

<\/p>\n

The quarter model
<\/p>\n

I’m trying to simulate a wall moving normal to a stationary wall with an amplitude ratio of 0.8 of the initial air gap (200µm)
Mesh elements are tetrahedrals, mesh size 100 µm
Dynamic mesh is set to layering and unified remeshing, cell height 20 µm
The model is laminar with air – ideal gas
Time step size =  5e-5 s<\/p>\n","protected":false},"template":"","class_list":["post-292617","topic","type-topic","status-closed","hentry","topic-tag-moving-deforming-mesh-2","topic-tag-negative-cell-volume"],"aioseo_notices":[],"aioseo_head":"\n\t\t\n\t\n\t\n\t\n\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t