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gas velocity looks weird in vicinity of inlet

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Old   June 21, 2011, 05:33
Default gas velocity looks weird in vicinity of inlet
Join Date: May 2010
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Hi Foamers,

The gas velocity looks weird when i am doing simulations with solver twoPhaseEulerFoam. The inlet velocity of gas =1.2213 m/s and liquid=0.9214 m/s. However the gas velocity in in vicinity of inlet is always smaller than the one of liquid (gas velocity is larger than liquid velocity elsewhere, see figures). But if I look deep into the problem, I could see a large drag force to push gas bubbles but it failed to speed them up in those cells... I have to mention that here the drag force (on purpose of debug.) is calculated by the velocities (Ua and Ub) not as it is in the solver (where the drag force is calculated by the flux phia and phib).

I have uploaded the case. BTW I am not quite sure about the setup of my pressure boundary conditions at inlet and at walls. I am still confused with BCs between zerogradient and buoyantpressure. Thanks

// Kai
Attached Images
File Type: jpg Ua.jpg (32.0 KB, 6 views)
File Type: jpg Ub.jpg (34.0 KB, 5 views)
File Type: jpg Ur.jpg (33.5 KB, 5 views)
Attached Files
File Type: zip (15.8 KB, 1 views)

Last edited by kaifu; June 21, 2011 at 10:11.
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