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July 28, 2013, 16:20 |
Good Cp using air, but wrong if using water
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#1 |
New Member
Join Date: Mar 2009
Posts: 22
Rep Power: 17 |
I am simulating a fluid jet impacting a wall. I get the correct pressure coefficient (Cp) distribution on the wall when using air.
When I try simulating it with water at the same Reynolds number, the Cp distribution is correct, however the value is off by a factor of 200. I have double checked that I am using the proper velocity and rho for calculating the Cp, but I can't figure out why I'm getting so low Cp. |
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July 29, 2013, 03:15 |
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#2 |
Senior Member
Artur
Join Date: May 2013
Location: Southampton, UK
Posts: 372
Rep Power: 19 |
By wrong Cp distribution do you mean wrong forces output or incorrect pressure values when viewed in paraview?
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July 29, 2013, 17:41 |
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#3 |
New Member
Join Date: Mar 2009
Posts: 22
Rep Power: 17 |
The Cp distribution is correct (looks like a bell curve), however the pressures given in Paraview are too low.
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August 5, 2013, 19:55 |
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#4 |
New Member
Join Date: Mar 2009
Posts: 22
Rep Power: 17 |
UPDATE
If I calculate the pressure coefficient using the surface pressure I got with the water and use rho_air, my results are good. This is what my transportProperties look like: Code:
transportModel Newtonian; nu nu [0 2 -1 0 0 0 0] 1.004e-06; DT DT [0 2 -1 0 0 0 0] 1.439e-07; Is there a reason why OpenFOAM would use nu_air even if I defined the one for water? I'm using icoFoam with temperature added. |
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