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-   -   Cavitation model in new fluent version (http://www.cfd-online.com/Forums/fluent/27817-cavitation-model-new-fluent-version.html)

John Lee August 4, 2000 16:48

Cavitation model in new fluent version
 
Have you tried the new cavitation-model in fluent ? Did you get good results for turbines and pumps ?

John

John C. Chien August 5, 2000 13:18

Re: Cavitation model in new fluent version
 
(1). What is a cavitation model? (2). Why do I need one? (3). Could you define a "good result" first? (4). I have been saying that 99% of the time I am getting the wrong answers by using cfd codes. So, naturally, it is very hard to get a good result. (5). But if you can explain to us the theory and the code used behind this cavitation model, then I guess, many of us can make some comments on it.

Joern Beilke August 17, 2000 12:51

Re: Cavitation model in new fluent version
 
A very stupid and arrogant answer. It would be much nicer if you only try to answer those question where you are able to contribute some usefull information.


John C. Chien August 17, 2000 20:03

Re: Cavitation model in new fluent version
 
(1). Yes, I agree with you. (2). It would be much nicer if one only ask questions which he has answers to it. And the vendors produce only codes which do not create stupid questions or questions with no apparent answers.

John Lee August 20, 2000 19:00

Re: Cavitation model in new fluent version
 
Dear John, (1) a cavitation model is a model, that models cavitation ! (2) If someone does not know what this is - no matter. It is not essential for 99% of fluid-mechanics. If you are interested in that topic look at a search-engine or at every book about pumps or turbines. (3) reasonable values for the behaviour of pressure and velocities, not correct ones (!) If 99% of your results are completely wrong, I'd stop calculating. A question: What is wrong ? (5) For the theory look at the literature. The implementation and simplification in the code seemed to be ok, but that seemed to be in all cfd-codes. And noone brought any reasonable results.

John C. Chien August 21, 2000 11:25

Re: Cavitation model in new fluent version
 
(1). I think, what you are saying is " a black box is a box with nothing in it". (2). A new model in a black box is still nothing in the black box. (3). If we have to ask someone that is this black box working? Then I guess he has no confidence in it at all. Using my definition, it is 99% wrong.


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