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-   -   Segregated or Coupled? High Speed Flow Mixing. (http://www.cfd-online.com/Forums/fluent/44224-segregated-coupled-high-speed-flow-mixing.html)

Mazhar Azim March 23, 2007 11:58

Segregated or Coupled? High Speed Flow Mixing.
 
Dear all,

Situation:

I am simulating flow mixing in a tee joint for compressible gas, where the flow speeds varies from 0.1 to 0.8 Mach.

I tried both segregated and coupled solvers & got difference in results in the recirculation zones created after flow mixing. The pressure distribution downstream also give different contour plots.

Question:

1- Based on flow details, with which solver should i continue my simulations?

2- Other than fluent help files, does anyone has any other reference for the crieteria of selection of the solver?

thanks to all for the time and expected suggestions.

Regards

Mazhar.


Seyed Farid Hosseinizadeh March 28, 2007 17:04

Re: Segregated or Coupled? High Speed Flow Mixing.
 
Hey: Can I see what is your numerical method's name? Maybe I can do some help. Thanks/Farid

Mazhar Azim March 29, 2007 10:53

Re: Segregated or Coupled? High Speed Flow Mixing.
 
Thanks alot for your reponse.

I am using fluent 6.2.16. The numerical scheme set up is summarized as:

Solver: segregated

Turbulence Model: K-epsilon realizable

Pressure Velocity Coupling: SIMPLEC

Skewness Correction: 0

All under relaxation factor 0.8 (pressure,density,body forces,momentum,turbulent KE, turbulent diss rate,energy)

Descretization Schemes:

Pressure ==> Standard

Density ==> First Order Upwind

Momentum ==> First Order Upwind

Turbulent KE ==> First Order Upwind

Turbulant Diss Rate ==> First Order Upwind

Energy ==> First Order Upwind

The grid is structured, aligned in flow direction.

For further information, when i ran these simulation they give satisfactory results till 0.4 Mach. BUT BEYOND THIS (0.5 - 0.8) THE SOLUTION DIVERGES IMMEDIATELY AS I SHIFT FROM INCOMPRESSIBLE TO COMPRESSIBLE.

Sorry for inconvinience in reading a lengthy message.

Thanks and Regards,

Mazhar.



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