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May 12, 2013, 01:25 
SIMPLE algorithm implementation, pressure correction error

#1 
New Member
David
Join Date: Feb 2013
Posts: 15
Rep Power: 5 
I have been implementing this SIMPLE algorithm to a 2D tunnel flow. I use inlet constant velocity boundary condition and outlet constant pressure boundary condition.
I can get very good flow velocity distribution, which have the max velocity in the center and zero on both tunnel wall. The max velocity magnitude also seems reasonable. But I cannot get good pressure distribution, the pressure inside the tunnel could be high up to 7 times of boundary pressure. And the strange part is the pressure distirbution seems didn't influence the velocity momentum calculation a lot, I can still get good velocity contour. Is there some one can give me some hint about this problem, which part I should look into? Thanks. 

May 12, 2013, 22:56 
HIs problem is really like me

#2 
New Member
David
Join Date: Feb 2013
Posts: 15
Rep Power: 5 
I am also implementing versteeg's book, the pressure correction got similar problem. The velocity distribution profile, pattern are all ok, but the magnitude value, if compared with slit flow theoretical value
u(y)=(dp/dx)H^2/8Miu*(1(y/0.5H)^2) the max velocity is always 50% higher than the theoretical number, I believe the problem is at pressure correction and don't know how to solve it. 

February 8, 2014, 01:15 
Simple

#3 
New Member
hadieliasi
Join Date: Apr 2011
Posts: 10
Rep Power: 7 
Hi.
I think you may use SIMPLER Algorithm that is better than SIMPLE algorithm because in SIMPLER, the pressure equation instead of pressure correction equation is solving directly. In SIMPLE even velocity distributions is correct but the pressure may not correct and needs to more iterations. but i think 2 way to solve your problem: 1At first check your code and be sure that is correct. may be the problem is about defining reference point for pressure. 2Please check b.c and be sure that they are correct. how do you define those b.c? 2Modify your code to solve simpler algorithm. It is very easy and you should change some parts of your simple code. in patankar's book " heat transfer and fluid flow " these methods are existed. i have teach and w2d code.If you need, I can send those you. 

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pressure correction, simple algorithm 
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