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#1 |
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When I have a wall I typically use "noSlip" as boundary condition for the velocity U also when dealing with turbulent flow.
At the same time I use turbulence models with wallfunctions for the turbulence variables. It does not seem like there are specific wallFunctions for the velocity. Is the answer that in practice the velocity U is indirectly determined by wallfunctions through the turbulence variables (that is modelled with wallFunctions)? |
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#2 |
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Robert
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To my knowledge, the typical expectation is that your velocity is Zero (0 0 0) at the wall. That is why you use a noSlip, or fixedValue (0 0 0) which does the same, boundary condition.
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#3 | |
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Quote:
So one has no slip at the wall, but do you know what one have between the wall and the 1st cell for U when one use e.g. nutUSpalding for nut at the wall? |
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#4 |
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Uwe Pilz
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There is no wall function for U because the flow is the result of your calculation. If you use only p and U, then you don't have any additional model for turbulence. If you use such a model (e.g. k-epsilon) this model influences the flow. It does that in a different way in the near of walls.
The wall function is not a property of the flow but a property of the model of turbulence.
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Uwe Pilz -- Die der Hauptbewegung überlagerte Schwankungsbewegung ist in ihren Einzelheiten so hoffnungslos kompliziert, daß ihre theoretische Berechnung aussichtslos erscheint. (Hermann Schlichting, 1950) |
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#5 | |
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Quote:
Thanks! |
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