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September 15, 2013, 02:12 |
Simulate a flow over hemi-sphere
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#1 |
New Member
Dinh
Join Date: Sep 2013
Posts: 10
Rep Power: 13 |
hi everyboby, I'm simulating a flow over a 3D hemi-sphere in two velocity direction.
With the direction is perpendicular to the arc plane, I got the Cd is about 0.42 which approximately with experiment results. It is good result. However, with the remain case, when the velocity is perpendicular to vertical plane, I got the Cd is about 1.277 ( while experiment result is about 1.12). In this case, I use k-omega SST model. Should my mesh has something wrong or should I use another model? I attached me mesh for this case. Please help me solve this problem. Thanks in advance my mesh : http://www.mediafire.com/?7q4x1t7iyy8s7av |
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September 15, 2013, 11:14 |
Mesh resolulation in wake and boundary layer
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#2 |
Senior Member
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Your mesh on surface of REV is good. But I see problems in wake region and boundary layer. I would suggest you to mesh in ICEM Hexa and use hemisphere shape at inlet and cylindrical shape at outlet.
You can also find the thread on meshing the same geometry in ICEM on cfd online ansys meshing forum and also I have uploaded YouTube video on the same. http://www.cfd-online.com/Forums/ans...-tunnel-2.html In fact, if you smart enough, you can use same files with little modification (mostly on geometry part as per your dimensions) |
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September 15, 2013, 11:39 |
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#3 | |
New Member
Dinh
Join Date: Sep 2013
Posts: 10
Rep Power: 13 |
Quote:
And I have one more question: whether haxagon mesh is better than Tet mesh for fluid flow? |
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September 15, 2013, 11:48 |
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#5 |
New Member
Dinh
Join Date: Sep 2013
Posts: 10
Rep Power: 13 |
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September 18, 2013, 04:17 |
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#7 |
New Member
Dinh
Join Date: Sep 2013
Posts: 10
Rep Power: 13 |
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September 18, 2013, 05:18 |
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#9 |
Senior Member
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Can you attach size function in the boundary layer and wake region? If so you can successfully predict drag. However hexa mesh mesh is always needed in the boundary layer region.
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September 18, 2013, 19:57 |
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#10 |
New Member
Dinh
Join Date: Sep 2013
Posts: 10
Rep Power: 13 |
here is my mesh
http://www.mediafire.com/view/naq828...08k-mesh_2.msh Is it good enough to calculate? One more thing, I know we create a inflation to model the boundary layer, but in my case, the flow seperates quickly because of the geometry of the body. So, if it is neccesary to create inflation on the surface of hemi-sphere Last edited by inspiron; September 19, 2013 at 04:51. |
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