# Converging then Diverging Residuals???

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 September 19, 2006, 07:24 Converging then Diverging Residuals??? #1 Erika Johnson Guest   Posts: n/a Hello, I was wondering if anyone has ever had any experience with residuals that intially start to converge and then after several iterations (i.e. 25,000+), they start to diverege??? I am working with the Reynolds Stress Model and I have decent convergence (1e-05) on everything except continuity (1e-2). In trying to get continuity to converge I let the simulation run and now at 25,000+ iterations I'm noticing that my Reynolds stresses, y-velocity, k and epsilon are starting to diverge slowly...Is the simulation adjusting itself in order to get the continuity to converge??? If it helps at all I'm simulating a flat plate boundary layer with super super fine mesh and low freestream intensity (0.2%). Any ideas??? Thanks so much, Erika

 September 19, 2006, 10:20 Re: Converging then Diverging Residuals??? #2 sam Guest   Posts: n/a It is normal dont worry

 September 19, 2006, 10:24 Re: Converging then Diverging Residuals??? #3 Erika Johnson Guest   Posts: n/a So then should I allow the solution to progress??? Will it eventually converge???

 September 19, 2006, 10:27 Re: Converging then Diverging Residuals??? #4 sam Guest   Posts: n/a yes. But not in absolute terms. It may start fluactuating between some value i.e diverging and converging. check the mass flow balance(it is ur gloval convergence)

 September 19, 2006, 10:30 Re: Converging then Diverging Residuals??? #5 Erika Johnson Guest   Posts: n/a Thanks for your help!

 September 19, 2006, 10:32 Re: Converging then Diverging Residuals??? #6 sam Guest   Posts: n/a wats ur msn or yahoo id?

 September 19, 2006, 10:35 Re: Converging then Diverging Residuals??? #7 Erika Johnson Guest   Posts: n/a I don't have one.

 September 19, 2006, 10:37 Re: Converging then Diverging Residuals??? #8 sam Guest   Posts: n/a which type of flow u r working on

 September 19, 2006, 10:45 Re: Converging then Diverging Residuals??? #9 Erika Johnson Guest   Posts: n/a I'm simulating a boundary layer experiment that was conducted in a wind tunnel with very low free stream turbulence intensity (0.02%). I'm actually trying to duplicate the turbulence intensity curves that Klebanoff published in his experiment from 1955 (Characteristics of Turbulence in a Boundary layer with Zero Pressure Gradient).

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