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Roe-Solver Instability at Mach=1

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Old   July 6, 2013, 08:34
Default Roe-Solver Instability at Mach=1
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Hey Guys,

can somebody tell me the reasons why Roes solver become instable at Mach=1? The literature says that the solver becomes a central-differences-method at Mach=1 because the right side of the Roe-flux vanishes, is this true? Isn't it only one eigenvalue of the jacobian that becomes zero?

Thanks for help!
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Old   July 7, 2013, 04:00
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hi
What software you use?
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Old   July 7, 2013, 06:36
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hi
What software you use?
I use Matlab to calculate a one-dimensional shock-tube-problem for the Euler-Equations.
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Old   July 7, 2013, 07:50
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how?is there such program in Matlab or you have written it?
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Old   July 7, 2013, 08:06
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how?is there such program in Matlab or you have written it?
I have written it.
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Old   July 8, 2013, 13:00
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Nobody any idea?
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Old   July 9, 2013, 21:13
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At sonic point one eigenvalue becomes zero. This leads to loss of dissipation in one of the eigenfields. It manifests as an entropy violating jump inside a sonic rarefaction. Look for "entropy fix" to overcome this problem.
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Old   July 10, 2013, 05:57
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At sonic point one eigenvalue becomes zero. This leads to loss of dissipation in one of the eigenfields. It manifests as an entropy violating jump inside a sonic rarefaction. Look for "entropy fix" to overcome this problem.
Ok i understand, thank you!
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