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Arnab January 27, 2005 16:38

Detailed Description
 
Hello,

My Warnings are :

*** WARNING #060 *** DENSITY OUT OF BOUND DUE TO PRESSURE CORRECTION AT CELL 509895 DENSITY= 1.2515E-03 LIMITER APPLIED GIVING UP AFTER PRINTING 50 #060 WARNINGS Total number of #060 warnings: 5820

AND

*** WARNING #057 *** EQUATION OF STATE IMBALANCE AT CELL 509774 IS 1.710664E+00 EQUATION OF STATE IMBALANCE FOUND AT MORE THAN 100 CELLS - PRINTOUT OF WARNING MESSAGE STOPPED

I want to give you more details of my simulation for you and others to better understand the problem and give me suggestions.

My CASE:

1.Transient, Moving mesh (Rotor moving at 10300 rpm and stators stationary).

2 stagnation inlets and 2 pressure outlets as it is a 4 port configuration.

3. Molecular properties: Ideal f (T,P) , Constant default properties for Air in terms of Molecular viscocity, Cp, Conductivity and Molecular weight.

4. Turbulence Model - K-epsilon High Re

Thermal Models - (conservation- static enthalpy, enthalpy- thermal)

Initialization - Default Initialization flow with 0 max vel and atmosphere pressure and temp.

5 Monitoring and Reference cells at outlet with atmospheric pressure assigned.

6. Max number of corrector stages : 50

Reduction in Residual for corrector stages = 0.25

under relaxation for pressure correction = 0.01

scalar solver - method - CG

Implicit Temporal Discretization

Solving for U, V,W, Pres, Turb KE, Turb Diss, T .

Differencing schemes - UD and MARS

7. Time step : 1.21 e -10 sec.

run for 0.005825 secs

Still I am getting these warnings at all time steps for almost all the cells i guess:

*** WARNING #060 *** DENSITY OUT OF BOUND DUE TO PRESSURE CORRECTION AT CELL 509895 DENSITY= 1.2515E-03 LIMITER APPLIED GIVING UP AFTER PRINTING 50 #060 WARNINGS Total number of #060 warnings: 5820

AND

*** WARNING #057 *** EQUATION OF STATE IMBALANCE AT CELL 509774 IS 1.710664E+00 EQUATION OF STATE IMBALANCE FOUND AT MORE THAN 100 CELLS - PRINTOUT OF WARNING MESSAGE STOPPED

Arnab January 27, 2005 16:57

Re: Detailed Description
 
Also I am getting this error sometimes when I use static conditions for inlet instead of stagnation:

After 1st Iteration:

Calculation stopped due to negative densities in more than 100 cells..

Help me!!!

Arnab

Somnath January 28, 2005 07:15

Re: Detailed Description
 
u can try by reducing the residual tolarances to avoid the negative density.


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