SIMPLE algorithm and coefficient

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 May 22, 2013, 03:58 SIMPLE algorithm and coefficient #1 New Member   sina gilassi Join Date: May 2013 Posts: 17 Rep Power: 5 According to the book `An introduction to computational fluid dynamic the finite volume method, H K Versteeg, first edition` page 139, the momentum equations are defined as follows: a(i,J)u(i,J) = SUM(a(nb)u(nb)) + (P(I-1,J) - P(I,J))A(i,J) + b(i,J) As SIMPLE algorithm needs P(guess) to change the above equation to scaler equation and then for each velocity u and v we have an equation. My question is about the coefficient of above equation which contains the F and D, both F and D equation contains u and v values. in page 142, the description of SIMPLE algorithm : 1) P(guess) 2) scaler equation --> iteration --> result = v(star) and u(star) 3) find P' with the continuity equation 4) correct all P,u and v 5) check the convergence 6) yes or no and loop my question is the coefficients ??!!!! their elements should be multiplied by the u(star) and v(star) ??? i am totally Someone helps me

May 22, 2013, 04:20
#2
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Philipp
Join Date: Jun 2011
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Quote:
 Originally Posted by sinagilassi ... My question is about the coefficient of above equation which contains the F and D, both F and D equation contains u and v values. ... my question is the coefficients ??!!!! ...
Now, what exactly is your question? Do you want to know how the coefficients are calculated, since they need the unknown velocities?
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 May 22, 2013, 04:28 #3 New Member   sina gilassi Join Date: May 2013 Posts: 17 Rep Power: 5 yes exactly, yes, yes, ... the mentioned book says: 1) guess P 2) v (star) and u(star) will be calculated ?? HOW they are calculated when the coefficient are unknown ??

 May 22, 2013, 04:43 #4 Senior Member     Philipp Join Date: Jun 2011 Location: Germany Posts: 1,297 Rep Power: 19 You always need to initialize all the variables. Also the velocities. Thus, you can use the initializations to calculate the coefficients. Later on you can use the "last known" velocities for that. __________________ The skeleton ran out of shampoo in the shower.

May 22, 2013, 05:27
#5
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sina gilassi
Join Date: May 2013
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Quote:
 Originally Posted by RodriguezFatz You always need to initialize all the variables. Also the velocities. Thus, you can use the initializations to calculate the coefficients. Later on you can use the "last known" velocities for that.
thank you man for all the responses

but I am still thinking

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