# Segregated or Coupled? High Speed Flow Mixing.

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 March 23, 2007, 10:58 Segregated or Coupled? High Speed Flow Mixing. #1 Mazhar Azim Guest   Posts: n/a 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.

 March 28, 2007, 17:04 Re: Segregated or Coupled? High Speed Flow Mixing. #2 Seyed Farid Hosseinizadeh Guest   Posts: n/a Hey: Can I see what is your numerical method's name? Maybe I can do some help. Thanks/Farid

 March 29, 2007, 10:53 Re: Segregated or Coupled? High Speed Flow Mixing. #3 Mazhar Azim Guest   Posts: n/a 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.