Too high mach number...
I have a complicated geometry which contains some narrow cross sections. In my tutorial simulation (see below) there is a simple choke. It is a 2D axisymmetrical geometry, the pressure ratio is 3.
The main settings:
- steady state
- total pressure inflow/static pressure outflow
- air ideal gas
- SST turb.modell
- high resolution
Based on the convergence history the simulation is converged. I don't understand the cause of the too high Mach number. The geometry doesn't contain Laval tube, this is a simple choke.
I have tried to set the expert parameter/high speed models but the result is unchanged.
Can the material model cause the problem?
...perhabs other ideas?
Thanks in advance;
Looks like a standard expansion shock to me. What don't you like about it?
If you want to see an expansion shock in real life have a look at a fighter jet engine exhaust, especially with afterburners on. You can see it clearly then.
As far as I know, the Mach number can not be larger than 1. Although a laval nozzle develops from the flow separations after the choke, but Ma=2.5??? :confused: In my opinion this is unrealistic...
I have some measurements to the original investigated geometry. The total temperature was measured before and after the choke. The total temp. is in the case of my simulation ~24C (after the choke). This value was ~15C in case of the measurement...
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