[FLASH-USERS] Supersonic Turbulence using the PPM method

[Christoph Federrath]

Hi Tristan,

for PPM, you can try nriem = 1000, which helped sometimes (in the past). Also reducing cfl helps. However, there is a limit to those tweaks. I would suggest to try the unsplit solvers. Dongwook Lee implemented a number of features to make them more stable, such as shock detection and automatic reduction of the cfl. We are using a different solver altogether (Waagan et al. 2011, JCP, based on work by Bouchut et al., which is not (yet) in the public flash repository though.

Best regards,
Christoph

> On 2 Jun 2021, at 19:21, Tristan <juwj at mail2.sysu.edu.cn> wrote:
> 
> Hello,everyone:
> 	I am working on a simulation	with high Mach number turbulence using the StirFromFile unit, I using the forcing_generator.F90 to generate the Driving force seed with the Mach at 12(by changed the st_energy). But I did’t know how to choose a suitable Solver for the Stir unit. 
> 	I tried the split PPM solver, and the two parameters to the flash.par:
> ```
> 	use_steepening = .false. # use contact steepening (originally for PPM) 
> 	hybrid_riemann = .true.
> ```
> My program broke down quickly, and the error output is:
> 
> Terminating execution.
> DRIVER_ABORT: Nonconvergence in subroutine rieman
> application called MPI_Abort(MPI_COMM_WORLD, 1) - process 46
> 
> I also attached the flash.par and the output file for you to check my work. If someone have a better Solver choice in Supersonic (Mach above 12) turbulence simulation. Please help me! 
> Thanks
> Best wishes!
> 
> <flash.par><slurm-4341014.out>