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-   -   Something not clear for me in Jasak's thesys (http://www.cfd-online.com/Forums/main/13685-something-not-clear-me-jasaks-thesys.html)

Lam June 20, 2007 03:53

Something not clear for me in Jasak's thesys
 
Hi all,

I've read the thesys of Jasak.

And in the part 3.8, when he speaks about the semi-discretized form of the momentum equation, I wonder where the "laplacian(nu,Grad(U))" is.

Because, he says: a_p*U_p=H(U)-Grad(p), where H(U)=-sum[a_n*U_n]+U0/deltaT

and div(UU)=a_p*U_p + sum[a_n*U_n]

First I guess that laplacian(nu,Grad(U))=a_p * U_p + U0/deltaT

But I'm quite not sure. Hope that somebody can tell me where the laplacian(nu,Grad(U)) term is, in the discretized form.

Thanks in advance,

Lam

Hrvoje Jasak June 20, 2007 06:16

Re: Something not clear for me in Jasak's thesys
 
Read it again: laplacian(nu,Grad(U)) also lives in a_p*U_p + sum[a_n*U_n], just like the convectin term - this is described in the discretisation chapter.

Hrv

Lam June 20, 2007 06:38

Re: Something not clear for me in Jasak's thesys
 
thanks to replying me.

Now it's clear. But I just have an other question:

what are the a_p and a_n coefficients in your thesis?

I guess that they are a mixt between the Flux and the V_p and V_N. But it'svery not cleasr for me.

Thanks in advance,

Lam


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