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Good Cp using air, but wrong if using water

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Old   July 28, 2013, 16:20
Default Good Cp using air, but wrong if using water
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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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Old   July 29, 2013, 03:15
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By wrong Cp distribution do you mean wrong forces output or incorrect pressure values when viewed in paraview?
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Old   July 29, 2013, 17:41
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The Cp distribution is correct (looks like a bell curve), however the pressures given in Paraview are too low.
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Old   August 5, 2013, 19:55
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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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