Hi Amir, On 19/11/2020 06:39, Amir Hossein Jafari Matin wrote:
1. The Error “Minimum sized time step rejected”, does it mean, that the simulation diverges? Sometimes the simulation goes on, when I just restart the simulation from the last solution, however sometimes I get the error at one specific time. I also tried to limit the time step using dt-max, but it did not work. If I turn off the PI controller, I get NaN values instead. I should mention that I have relatively fine mesh (comparing with your T106c test case). Do you have any suggestions, how I can prevent this error?
This typically means that the simulation is diverging. There are many possible reasons for this; including your mesh and start-up procedure.
2. Do I need to use anti-ailiasing just for Polynomial orders higher than 2? Did you use it for the T106c case at P2 and Re=80000?
Here it very much depends on the mesh, polynomial order, and Reynolds number. For this particular case I did not run with anti-aliasing, however I did need to be careful with how I started the simulation (running at p = 1 for a period of time before restarting at p = 2).
3. In my understanding the reference Reynolds number is not defined in pyfr in case of non-dimensionalaizing, therefore we have to eliminate it by choosing a specific reference dynamic viscosity, namely Mu_t0 = rho_t0 * a_t0 * Lc (Mu_t0 : Reference dynamic viscosity, rho_t0 : Reference density, Lc : Reference Lenght). So that the reference Reynolds-number would be 1. Is that correct?
The Reynolds number is typically fixed by changing the viscosity, yes. Regards, Freddie. -- 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 view this discussion on the web, visit https://groups.google.com/d/msgid/pyfrmailinglist/8a14fc5b-34fe-9a88-3403-a0a9b68e6559%40witherden.org.
