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Problem on LES of incompressible free jet

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Old   September 20, 2017, 11:02
Default Problem on LES of incompressible free jet
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I am doing a LES of incompressible free jet with the Re=70000. The computation domain extents 15D in streamwise and 10D in radial direction. Max co is adjusted to less 0.6.
When the flow developed to the outlet, backflow appeared, k exploded then case crashed.
boundary conditions at the outlet I set as below:
U:zeroGradient;
p:fixedValue;
k:inletOutlet;
nuSgs:zeroGradient
I have simulated a similar jet with lower Re(30000), and not encountered this problem. So I am confused with this and have no idea on this issue.
Could anyone give me some advise how to solve this problem?
Thanks!
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Old   September 25, 2017, 20:58
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Using fixedMeanValue for p at outlet,flow can leave the domain naturally.
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Old   September 25, 2017, 21:08
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Hi Huang,

What is your BC at the top domain for velocity?

Regards
Robert
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Old   September 25, 2017, 21:19
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Quote:
Originally Posted by rob3rt 0ng View Post
Hi Huang,

What is your BC at the top domain for velocity?

Regards
Robert


zeroGradient


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