# laminar flow on flat plate

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 September 1, 2006, 11:44 laminar flow on flat plate #1 AmirFluid Guest   Posts: n/a Sponsored Links I have used Patankar code to simulate laminar flow over flat plate. Results show some velocity overshoot just next to the plate surface. Also pressure has sudden rise at the first point above starting of the plate. does anyone know the reason?

 September 2, 2006, 08:53 Re: laminar flow on flat plate #2 Siddharth Guest   Posts: n/a Dear Amir, I don't have much idea about Patankar code. But most likely it is due to improper grid refinement near wall or near-wall treatment scheme that is used. Because velocity and hence pressure gradient is high in this region. For that you need either more number of cells near to wall or pick up good descretization scheme. Regards, Sidd

 September 4, 2006, 04:05 Re: laminar flow on flat plate #3 mar Guest   Posts: n/a Hi Using 10 to 20 points in the boudnary layer you must find the Blasius solution for the laminar plate. If your grid complies with these requirement the problem can be in the boundary conditions. First check the wall BC (u=v=0 dp/dn=0 dT/dn=0) Second the Inlet condition. Regarding the inlet you can have two choice: 1) you impose the Euler inlet condition because you simulate the leading edge (i.e. your plate doesn't start at i=1 but, for example at i=10 and from i=1 and i=9 you impose simmetry condition) 2) you impose a velocity profile at the inlet because you do not simulate the trailing edge (your plate starts at i=1 and so the Euler inlet condition is not valid).

 September 7, 2006, 10:01 Re: laminar flow on flat plate #4 Bounecer Guest   Posts: n/a Please how to implement that same boundary conditions for airfoil and using structured O-grid

 February 26, 2010, 06:24 #5 Member   varun Join Date: Apr 2009 Posts: 35 Rep Power: 10 hey.... i'm having the same problem... i'm taking u_freestream as 100.... velocity is shooting @ the point next to wall... and then gradually it is receding... some1 suggested me to have varible width b/w grid points along y-axis.... how do i exactly do that...???

 March 4, 2010, 08:01 #6 Member   varun Join Date: Apr 2009 Posts: 35 Rep Power: 10 i got the results........ who so ever encounters such problem.... the problem is with dx values you r taking..... they r too large... reduce them and your code works fine.....

 April 25, 2010, 11:07 #7 Member   Join Date: Jul 2009 Posts: 70 Rep Power: 10 Hello everyone, I've got the same problem with AmirFluid. In my simulation I used the flat plate that starts at x=0, so as Mar mensioned, the Euler inlet condition is not valid. Can anyone tell me what is the Euler condition here? I'll try to refine the mesh at x-direction as varunjain89 said. Thanks for any help!

 June 22, 2010, 05:49 #8 Member   Ardalan Join Date: Feb 2010 Location: Baku Posts: 50 Rep Power: 9 can anyone send me the patankar code????? I will be thankful thelastarmageddon@yahoo.com Last edited by Ardalan; June 22, 2010 at 07:01.

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