[Stargazer]

Hi,

I am working on an unsteady simulation of vehicle aerodynamics. I used sst-kw turbulence model and coupled flow solver. I found that the residuals have a rising tendency as the simulation goes on(attached figure 1). The residuals in each time step can drop by 3 orders of magnitude to 10E-4~-5(figure 2). No divergence occurred. Is this a reasonable residual? And what might be the cause of the overall rising residuals? Looking forward to your professional advice. Thank you!

[arjun]

Yes this can happen.



"And what might be the cause of the overall rising residuals?"


As the flow is converging the yplus, shear etc are changing at the walls and this is what most probably causing this behaviour. Or some sort of limiting inside that is causing this non smooth behaviour.