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compressibility and cavitation!!

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Old   March 5, 2005, 22:39
Default compressibility and cavitation!!
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I have a problem with cavitation. The pressure dependent density description for the liquid works fine as long as I do not activate cavitation. But when activating the cavitation I get NaN for the produced species in the first Iteration (although there is no cavitation at the beginning of the simulation at all).

As I using the cavitation model,density of the heavy fluid just can be set as a constant number.Can I using some method to solve this problem?

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Old   March 14, 2005, 14:17
Default Re: compressibility and cavitation!!
khalid sultan
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hi generally speaking when you get NaN; it means you are dividing by zero ( or a very small number ) or you are trying to take the root of a negative number - of course if we exclude the case that you are using a value without initailization - here are some Hints:

1- try to use a debugger ( i.e. ddd if your code is in

c++ ); this will help you to locate the location of

the problem.

2- If the above does not help, I suggest that you

examine carefully the places where you interpolate

flow variables ( wether the pressure or the

temperature is wrongly negative ).

3- look at the bright side

at least you know that your problem is related to

cavitation, you don't have to search anywhere else!

Go directly to the place that handles this term.

4- when you find the place where the error occurs,

try to put =>some kind of a limiter<= to avoid the

( non-positivity ).

Hoping it would help . . . good luck

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Old   June 27, 2005, 17:16
Default Re: compressibility and cavitation!!
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hi, i'll like to know more about cavitation
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