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October 7, 2002, 18:08 |
Extapolation of forces with wall laws.
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#1 |
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Hi. Doe's anybody know if/how it is possible to extraplate the shear forces from the values obtained with k-epsilon wall laws in order to get more accurate lift and drag force calculations.
That is, I want to be able to obtain values of the forces directly at the walls even though I have used wall laws and thus don't have access to the values at the walls. |
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October 9, 2002, 04:55 |
Re: Extapolation of forces with wall laws.
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#2 |
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I guess the friction velocity of the wall law can give the wall shear.
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October 9, 2002, 12:36 |
Re: Extapolation of forces with wall laws.
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#3 |
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Well as I see it by using the friction velocity to get the shear stress you only get the value at y+=50 or so, and not at the actual wall where y+=0. Maybee there's not much difference, anybody that has experience with this?
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October 14, 2002, 05:46 |
Re: Extapolation of forces with wall laws.
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#4 |
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u+ = sqrt(Tau_wall/rho) where Tau_wall is the shear at the wall.
Since you have y+ at point y, it comes : nu*y+/y = u+ = sqrt(Tau_wall/rho) This is under log law equilibrium hypothethis, otherwise.... Hope that helps, Sylvain |
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