Mesh grading for aerodynamic

Christoph Grabietz

Hello together,

I would like to evaluate the aerodynamic properties of an object with hyperworks cfd and the FarField condition. In order to use this type of boundary condition my simulation domain must be relatively big. To cut simulation time as much as possible I would like to apply a gradient to my mesh. That means that at the center of my domain (where the object is placed) I need a fine mesh while at the boundary of the domain the mesh can be much more coarse. Is there any way to achieve this with hyperworks or do I need an external meshing software. I have tried to apply different surface mesh densities to my object and the FarField surface but that has not worked.

A good representation of the mesh can be obtained here:

https://2021.help.altair.com/2021.2/hwsolvers/acusolve/topics/acusolve/turbulent_flow_over_a_naca_airfoil.htm

 

Best regards

Christoph

 

 

acupro

If you have separate Volumes in your geometry, you can use Volume Mesh controls.  Otherwise, you use Zones in the Mesh ribbon to define regions/zones for mesh control, independent of the actual geometry surfaces/volumes.    So likely a combination of Surface mesh controls and Zones mesh controls - plus boundary layers.  The average size specified in the Volume mesh panel (generating the mesh) would be the largest size - then use the others to get smaller mesh where you desire.

Christoph Grabietz

acupro_21778 said:

If you have separate Volumes in your geometry, you can use Volume Mesh controls.  Otherwise, you use Zones in the Mesh ribbon to define regions/zones for mesh control, independent of the actual geometry surfaces/volumes.    So likely a combination of Surface mesh controls and Zones mesh controls - plus boundary layers.  The average size specified in the Volume mesh panel (generating the mesh) would be the largest size - then use the others to get smaller mesh where you desire.

Thanks for your answer. Yes I was aware of the Zone mesh controls but then I have rather "sharp" edges within the mesh itself and not a smooth transition. I thought that there might be a more elegant solution.

acupro

Christoph Grabietz said:

Thanks for your answer. Yes I was aware of the Zone mesh controls but then I have rather "sharp" edges within the mesh itself and not a smooth transition. I thought that there might be a more elegant solution.

If you mean the sizes change more rapidly, you may try reducing the 'Mesh Growth Rate' when you generate the volume mesh - or define more zones to give more gradual growth.

Christoph Grabietz

acupro_21778 said:

If you mean the sizes change more rapidly, you may try reducing the 'Mesh Growth Rate' when you generate the volume mesh - or define more zones to give more gradual growth.

I think Growth Rate will do the trick for me. Thanks