Hi Sam,
I think you need to tune artificial viscosity coefficients which relies on solution and mesh size. >From the Persson's paper (AIAA 2006-0112), max-artvisc ~ h/p, s0~1/p^4 and kappa is chosen empirically sufficiently large so as to obtain a sharp but smooth shock profile. I think you may adjust max-artvisc if you refine your mesh. As I mentioned before, forward facing step problem may be tough to solve with artificial viscosity (https://groups.google.com/d/msg/pyfrmailinglist/bwicPvZb1B8/Z07K4OCjCgAJ). Please try a problem with oblique shock or mild normal shock first. Regards, Jin Seok Dr. Jin Seok Park PhD ________________________________ From: [email protected] <[email protected]> on behalf of SAM WANG <[email protected]> Sent: 03 November 2017 00:47:57 To: PyFR Mailing List Subject: [pyfrmailinglist] Supersonic flow test Dear all, I am now testing the supersonic forward step test recently. I also find another guy once trying to do that case, while I follow the suggestions and tried to reproduce the results. I copied the .ini file from Jin Seok https://groups.google.com/d/msg/pyfrmailinglist/bwicPvZb1B8/Z07K4OCjCgAJ, but changed the mesh file as attached. All the conditions are the same. 1. Test the corase mesh, each grid size is 0.0125, uniformly distributed.The results are like this. I think this is not correct. Then I test the finer mesh, each grid size is 0.00625, uniformly distributed. But it gives me minimum sized time step rejected even though timestep is reduced to 1e-10 if "controller" is "pi", and RuntimeError: NaNs detected at t = 0.009999999999999995 when "controller" is "none". Peter said this may be due to the doamin is under-resolvable https://groups.google.com/d/msg/pyfrmailinglist/wVJ4pj0unxQ/Jj5taiZyAQAJ. And the suggestion is increase the mesh resolution. I am quite confused now. 2. When Mach number increases to 3, both coarse and fine meshes would fail. Could anyone give me a hint to solve this? Besides, could anyone tell me if the parameters in "solver-artificial-viscosity" or parameters in "solver-interfaces" could affect results very much? If they do, could anyone tell me how to change those parameters correspondingly? Thank you all in advance. Regards, Sam <https://lh3.googleusercontent.com/-FqpnvalF55g/Wfu4pJIyQZI/AAAAAAAAAOk/ydYovfWOjfQuhmnRs1ZCt7qsKbRIivGpACLcBGAs/s1600/pressure.png>[https://lh3.googleusercontent.com/-EEGiIE2j-Kw/Wfu42aBXPLI/AAAAAAAAAOo/XJP1vMVETSENveag5zSowlptQV5DRDPnACLcBGAs/s200/screenshot.png]<https://lh3.googleusercontent.com/-EEGiIE2j-Kw/Wfu42aBXPLI/AAAAAAAAAOo/XJP1vMVETSENveag5zSowlptQV5DRDPnACLcBGAs/s1600/screenshot.png>[https://lh3.googleusercontent.com/-FqpnvalF55g/Wfu4pJIyQZI/AAAAAAAAAOk/ydYovfWOjfQuhmnRs1ZCt7qsKbRIivGpACLcBGAs/s200/pressure.png]<https://lh3.googleusercontent.com/-FqpnvalF55g/Wfu4pJIyQZI/AAAAAAAAAOk/ydYovfWOjfQuhmnRs1ZCt7qsKbRIivGpACLcBGAs/s1600/pressure.png> -- You received this message because you are subscribed to the Google Groups "PyFR Mailing List" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]<mailto:[email protected]>. To post to this group, send email to [email protected]<mailto:[email protected]>. Visit this group at https://groups.google.com/group/pyfrmailinglist. For more options, visit https://groups.google.com/d/optout. -- You received this message because you are subscribed to the Google Groups "PyFR Mailing List" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send an email to [email protected]. Visit this group at https://groups.google.com/group/pyfrmailinglist. For more options, visit https://groups.google.com/d/optout.
