Learning Forum

[Masoud Hatami]

Hi to all

I am new to ANSYS CFX, and I'm trying to simulate the squish oil on simple geometry. I attached the geometry here. I'm using one sector of a cylinder. At first, I moved the bottom surface toward the upper surface about 0.08 mm ( all the thickness is 0.1 mm) and calculated the force on the upper surface, which was 0.66 N. So at the next step, I tried to impose this force on the bottom side to see if it reached the 0.08 mm displacement or not. Unfortunately, after a few time steps, the calculated force by the software reaches 0.66 N and starts to oscillate. My question is: shouldn't force reach 0.66N when the displacement is 0.08mm? ( I used the unspecified option for side walls and opened with 0 Pa with unspecified walls.)

[CFD_Friend]

Hi Masoud,

Hope the mesh is not skewed at that level of displacement. I suppose the movement is only in the z direction, so I would advise you to have a sweep mesh in that direction with hex elements. Hex elements can be skewed to a larger extent than tet. Then if all things look right, just run the case in transient mode and visually inspect how the mesh deforms, also to make sure that all the boundary conditions are correct.

[Masoud Hatami]

Thanks for your response CFD_Friend

Actually, I'm using the sweep mesh, and I have no problem with the mesh. but I dont know how to run the case visually during the simulation. I checked the results in CFD-Post, and the deformation of the mesh was OK.