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April 14, 2009, 11:31 |
Simulation Quickly Diverging
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#1 | |
Member
Join Date: Mar 2009
Location: Texas
Posts: 33
Rep Power: 17 |
I am trying to run a steady, implicit simulation using the SST k-w model with the geometry shown in the two pictures below. I am using symmetric boundary conditions to make use of the symmetry of the problem with pressure inlet/outlet boundary conditions. Currently I am using first-order discretizations of all the equations
I can't get the solution to go past the first ten iterations. I get warnings about the temperature, absolute pressure, and the turbulent viscosity being limited at different iterations. I also get warnings of reversed flow at the inlet and the outlet, but I have gotten by those before after the first 20 or so iterations in past simulations with different geometries. Final the code dies with the message: Quote:
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April 14, 2009, 14:05 |
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#2 |
Super Moderator
Maxime Perelli
Join Date: Mar 2009
Location: Switzerland
Posts: 3,297
Rep Power: 41 |
*do you get also problem if you disable energy equation?
*calculations with pressure inlet and pressure outlet are more difficult to get converged. An initial guess with the half of drop pressure may help. *What is the max skewness of your mesh? |
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April 14, 2009, 16:26 |
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#3 | |||
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Join Date: Mar 2009
Location: Texas
Posts: 33
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Quote:
Quote:
Quote:
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April 15, 2009, 00:31 |
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#4 |
Super Moderator
Maxime Perelli
Join Date: Mar 2009
Location: Switzerland
Posts: 3,297
Rep Power: 41 |
ok, than it is linked to the energy equation.
Regarding the skewness, I don't think it is the reason, but I would recommand you to reach an mesh with skewness below 0.9. For the pressure-BC, I meant, that you can initialize your solution with gauge pressure equal to the half of your drop pressure |
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April 15, 2009, 10:14 |
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#5 |
Member
Join Date: Mar 2009
Location: Texas
Posts: 33
Rep Power: 17 |
Ok thanks. I will work on my mesh and try the initialization idea you suggested.
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