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-   -   Riemann solvers Q2 (https://www.cfd-online.com/Forums/main/69540-riemann-solvers-q2.html)

shuo October 26, 2009 22:24

Riemann solvers Q2
 
Hi all,

I have coded a HLLC WAF (weighted aberaged flux) Riemann solver to simulate a supersonic impinging jet issued from a DC-D nozzle. The Euler equations are solved with slip wall B.C. It is appropriate to use Riemann solver to extract acoustic information from the flow? And is it ok to introduce instability at the nozzle exit to extract turbulent fluctuations?

Regards

Shuo

Killercam November 27, 2009 11:45

Shuo,

Riemann solvers are typically used in conjunction with a Godunov scheme, and thats what your HLLC scheme is based around. This is used for non-dissapative regimes where the equations can be recast as a hyperbolic system of PDEs, or a system of conservation laws. The Riemann solver can extract nothing, it is used to obtain the intercell numerical fluxes at the cell boundaries - thats it (which is complicated in its own right). I am not sure if I understand you question, but these Godunov scheme are mainly used to resolve wave propagation, and can indeed resolve the sound/pressure/contact waves in such Newtonian flows - if this is you question the answer is yes.

See any papers on Godunov solvers for tests you can undertake to understand the effect of wave propagations in such flows.

Hope this has helped.

Dr. Killercam


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