Hi Manuel, The issue is likely to be one of resolution if the simulation works at Re = 4080. You can therefore try (probably substantially) refining the mesh in the region of the boundary layer and around the regions of separation. I would caution that at Re = 408k you're likely to struggle with a compressible simulation. This is because the compressible solver is explicit in time, and therefore will have quite a severe time restriction at the required resolution levels in the boundary layer. This being said we have done flat plate simulations up to O(100k) -- perhaps trying an intermediate Reynolds number around 50k might give you some indication of the resolution/timestep required. Cheers, Dave

On 20 Jul 2016, at 09:21, Gipperich, Manuel <manuel.gipperich@student.uni-siegen.de> wrote:

Hi all,

I need help for my simulation of the flow over a NACA 0012 Airfoil. I try to simulate the flow with a mach Number of M=0.4 and a reynoldsnumber of Re=408000. In every test my simulation is terminated with the message: NaN found in variable "rhou", terminating NaN found in variable "rhov", terminating NaN found in variable "E", terminating. I started the simulation with the same mach number and a lower reynoldsnumber of 4080 and it worked. So my question is, is there any solution for that problem to fix the instability of the simulation?

Here is my SolverInfo data which i entered in the .xml File. Is it possible that an other UpwindType will fix the problem?

<SOLVERINFO> <I PROPERTY="EQType" VALUE="NavierStokesCFE" /> <I PROPERTY="Projection" VALUE="DisContinuous" /> <I PROPERTY="AdvectionType" VALUE="WeakDG" /> <I PROPERTY="DiffusionType" VALUE="LDGNS" /> <I PROPERTY="TimeIntegrationMethod" VALUE="ClassicalRungeKutta4" /> <I PROPERTY="UpwindType" VALUE="HLLC" /> <I PROPERTY="ProblemType" VALUE="General" /> <I PROPERTY="ViscosityType" VALUE="Variable" /> </SOLVERINFO>

My simulation runs with a CFL-number of 0.7.

Thanks for any hint. If you need more information, please let me know .

Best regards

Manuel Gipperich _______________________________________________ Nektar-users mailing list Nektar-users@imperial.ac.uk https://mailman.ic.ac.uk/mailman/listinfo/nektar-users

-- David Moxey (Research and Teaching Fellow) d.moxey@imperial.ac.uk | www.imperial.ac.uk/people/d.moxey Room 364, Department of Aeronautics, Imperial College London, London, SW7 2AZ, UK.