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reflected shock in a shock-tube

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Old   April 8, 2009, 08:34
Question reflected shock in a shock-tube
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mathias kiesel
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hello,
i'm working with ansys-cfx since few weeks and i try to simulate the pressure-distribution in a shock-tube after the origin shock and the second, wall-reflected, shock.
During i'm satisfied with the calculated pressure-values after the first shock, the pressure-distribution after the reflected shock shows bad-damped oscillations i can't avoid.

do you have any hints how i can improve my simulation?
thanks
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Old   April 8, 2009, 20:33
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Glenn Horrocks
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Hi,

Avoiding oscillations in shock waves is a difficult issue. I assume you are using the high-res 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
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Old   April 9, 2009, 10:07
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mathias kiesel
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Hi glenn,
in my very first calculations i used second-order-euler-equations with a high-res-scheme. 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 high-res and upwind-scheme didn't change the results very much while using first-order-euler

thanks for your answer
matt
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Old   April 9, 2009, 10:18
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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).
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Old   April 9, 2009, 12:13
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mathias kiesel
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Hi timon,
thank you for the hint. I will try it soon and report then about my results.
thanks
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Old   January 24, 2013, 20:15
Default Shock tube simulation
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cfd
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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?

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Thanks
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Old   February 4, 2014, 17:43
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Ehsan
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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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