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Solution not converging, but oscillating residuals around a constant value |
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February 7, 2012, 07:29 |
Solution not converging, but oscillating residuals around a constant value
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#1 |
New Member
Irene
Join Date: Feb 2012
Posts: 1
Rep Power: 0 |
Hi Fluent users,
I am a new fluent user and I am analysing an impingement system for a vane internal cooling passage, using a realizable k-eps model. I started using a incompressible ideal gas, the solution converged without any problems but the calculated density was completely wrong, so I changed the material as an ideal gas. Now my solution doesn't converge anymore: all the residuals oscillate around a constant value, and in particular the continuity residuals oscillate around a value which is far from the convergence criteria one. I tried to change the under relaxation factors (it dumps the oscillatins but it doesn't improve the convergence), to use a finer mesh and to use the fluent mesh adaptation tool but without any results. Can anbody help me? Cheers Irene |
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February 7, 2012, 12:21 |
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#2 |
New Member
Join Date: Feb 2011
Location: France
Posts: 9
Rep Power: 15 |
It is difficult to judge from the few information you gave
What is the pressure and velocity value at the injection system (or maximum pressure in the system) ? Do you have good values of y+ ? Did you check the quality of your mesh ? Below are a few things you could try : - Using the density based solver - start with a lower mass flow (or velocity or pressure) inlet and increase it gradually - Start by an inviscid flow then add turbulence GG |
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February 7, 2012, 12:55 |
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#3 |
Senior Member
Ali
Join Date: Jan 2012
Location: Pakistan
Posts: 134
Rep Power: 16 |
I think your case is transient! not steady-state.
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convergence issues, oscillating residuals |
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