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AmirFluid September 1, 2006 11:44

laminar flow on flat plate
 
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?

Siddharth September 2, 2006 08:53

Re: laminar flow on flat plate
 
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

mar September 4, 2006 04:05

Re: laminar flow on flat plate
 
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).


Bounecer September 7, 2006 10:01

Re: laminar flow on flat plate
 
Please how to implement that same boundary conditions for airfoil and using structured O-grid

varunjain89 February 26, 2010 06:24

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...???

varunjain89 March 4, 2010 08:01

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.....

nvtrieu April 25, 2010 11:07

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!

Ardalan June 22, 2010 05:49

can anyone send me the patankar code?????
I will be thankful
thelastarmageddon@yahoo.com


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