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July 3, 2013, 02:03 |
outflow BC's?
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#1 |
Senior Member
Ehsan
Join Date: Oct 2012
Location: Iran
Posts: 2,208
Rep Power: 26 |
what set of BC's we can put in output flow boundaries?
One that i have test is fixedValue of pressure. It makes the pressure of neighbor internalField values of pressure goes higher than around cells in compressible cases. Another may be fixedValue velocity,but i saw some crash in this selection. Can we set both velocity and pressure there from CFD view? totalPressure is unstable on outflow. What are the experiences my friends has ever had on this topic?
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July 3, 2013, 04:18 |
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#2 |
Senior Member
Mohsen KiaMansouri
Join Date: Jan 2010
Location: CFD Lab
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Dear Ehsan
the b.c. for presurre at the outlet is like: Code:
outlet { type fixedValue; value uniform 0; } the type of b.c. for velocity depends on your outlet boundary. if your outlet boundary is far enough so that you don't have any reverse flow then the zeroGradient is a suitable choice Code:
outlet { type zeroGradient; } http://www.cfd-online.com/Forums/ope...tml#post385820 good luck
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July 3, 2013, 08:49 |
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#3 |
Senior Member
Ehsan
Join Date: Oct 2012
Location: Iran
Posts: 2,208
Rep Power: 26 |
Hi Mohsen
I have a problem in compressible flows outlet BC on p. p in neighbour cells of the patch goes very high. could you have a look into it? its a simple tube that only part of right wall is open.I need p on BC be 800000 but it seems it can't decrease below a limit(I'm not sure about the exact value but maybe around 1500000) why its so?its numerical or physical?mean in real world pressure at outlet can't be decrease more from a specific pressure?
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