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-   -   How to get probability density function (PDF) in OpenFoam? (https://www.cfd-online.com/Forums/openfoam/66015-how-get-probability-density-function-pdf-openfoam.html)

 openfoam15 July 3, 2009 04:10

How to get probability density function (PDF) in OpenFoam?

such like beta distribution function or battlement PDF. If not, Is there some mathematic function to calculate integration(detail: 1-dimension, interval 0 to 1)?

 ivan_cozza July 3, 2009 04:19

Quote:
 Originally Posted by openfoam15 (Post 221333) such like beta distribution function or battlement PDF. If not, Is there some mathematic function to calculate integration(detail: 1-dimension, interval 0 to 1)?
Can you give more details on your question?
You need to evaluate random numbers with a certain PDF?

 openfoam15 July 3, 2009 04:44

Thanks!
Here it is:
I need to calculate PDF such like fai(f)=(f^(v-1))*((1-f)^(w-1))/B(v,w), where B(v,w)=Integration of x from 0 to 1: {(x^(v-1))*((1-x)^(w-1))*dx}, v and w already known.

 openfoam15 July 3, 2009 06:40

and then calculate integration of f between 0 to 1: {C_dimessionless*fai(f)df}

 openfoam15 July 3, 2009 07:25

about calculate the fluctuation of specie's concentration.