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xhliu1 March 5, 2005 22:39

compressibility and cavitation!!
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?

khalid sultan March 14, 2005 14:17

Re: compressibility and cavitation!!
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 :)

ti June 27, 2005 17:16

Re: compressibility and cavitation!!
hi, i'll like to know more about cavitation

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