reflected shock in a shocktube
hello,
i'm working with ansyscfx since few weeks and i try to simulate the pressuredistribution in a shocktube after the origin shock and the second, wallreflected, shock. During i'm satisfied with the calculated pressurevalues after the first shock, the pressuredistribution after the reflected shock shows baddamped oscillations i can't avoid.:( do you have any hints how i can improve my simulation? thanks 
Hi,
Avoiding oscillations in shock waves is a difficult issue. I assume you are using the highres differencing scheme? That should minimise the oscillations but still give you second order accuracy in most regions of the flow. Also what time differencing scheme are you using? Glenn Horrocks 
Hi glenn,
in my very first calculations i used secondordereulerequations with a highresscheme. I got very bad oscillations behind my first shock. Changing to first order in euler equations improved the results for the first shock but with still unacceptable oscillations behind the reflected shock. Changing between highres and upwindscheme didn't change the results very much while using firstordereuler thanks for your answer matt 
Try switching on "high speed numerics" in the advanced panel of the solver control. This enables some numerical techniques specifically aimed at dealing with shock oscillations/instabilities (such as the carbuncle effect).

Hi timon,
thank you for the hint. I will try it soon and report then about my results. thanks 
Shock tube simulation
Hello,
I am new user of cfx and I want to simulate shocktube with two different gases, Is there any body could help me in defining the two different component of fluid which I have to use in this simulation? Regards Thanks 
Hi
a question: does the flow behind the reflected shock wave have a total pressure bigger than the original driver gas? is it correct? 
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