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December 7, 2013, 19:26 |
Velocity not zero during flow reversal
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#1 |
Member
Charlie
Join Date: Dec 2010
Location: USA
Posts: 85
Rep Power: 15 |
Hi,
I tried to simulate oscillatory channel flow using twoPhaseEulerFoam, the turbulence closure is k-Epsilon model. I use oscillatory pressure gradient to drive the flow, however, I found that the velocity of free stream at the flow reversal is not zero( very small), and it would grow when the case runs longer, could any one give some hint? What causes this problem? How to avoid this? The following is the momentum equation: fvm::ddt(Ub) + fvm::div(phib, Ub, "div(phib,Ub)") - fvm::SuSp(fvc::div(phib), Ub) == pressure gradient+ other terms Perhaps, it's more informative that I point out the fvSchemes that I use: ddtSchemes { default backward; } divSchemes { default none; div(phia,Ua) Gauss limitedLinearV 1; div(phib,Ub) Gauss limitedLinearV 1; div(phib,k) Gauss limitedLinear 1; div(phib,epsilon) Gauss limitedLinear 1; ... } One more question, just out of curious, why doesn't the program complain about missing definition of div(phib) in fvScheme? Thanks!! |
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August 14, 2014, 09:00 |
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#2 |
New Member
Sina Saremi
Join Date: May 2011
Location: Copenhagen, Denmark
Posts: 5
Rep Power: 14 |
Hi Charlie,
I know its quite long time since you have posted this question,,, but I am facing somewhat the same type of problem when having an oscillatory pressure gradient. The mean flow begins to rise and its not zero anymore at the reversal... Have you managed to find a solution for this? Sina |
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drift velocity |
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