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-   -   Setup of flat plate problem for laminar layer (https://www.cfd-online.com/Forums/main/91319-setup-flat-plate-problem-laminar-layer.html)

 pankos August 7, 2011 07:47

Setup of flat plate problem for laminar layer

Could someone to tell me what boundary conditions must be put at flat plate problem for laminar boundary layer?

I have solved the problem with below boundary conditions but i see a problem (incresment of density) at left lower corner at which connect the left boundary with symmetry plane.

Left boundary: specify: pressure, all velocities
upper boundary: same of left
right boundary: all gradients are zero
left lower (x<0): symmetry
right lower (x>0): viscous wall

 cfdnewbie August 8, 2011 19:43

sounds like you are overspecifying the lower left boundary, or you are having accuracy issues. a rise in density at that point means that you have created a stagnation point there, which is due to your flow coming from an Euler (symmetry wall) to a Navier Stokes (viscous) wall!

 panou August 9, 2011 03:25

No, i do not refer at stagnation point at connection of symmetry and wall but at start of symmetry plane (at left lower corner of domain).
As i see , some information of domain arrive here and after increse the density except of reflection of information.

 cfdnewbie August 9, 2011 17:37

Quote:
 Originally Posted by panou (Post 319415) No, i do not refer at stagnation point at connection of symmetry and wall but at start of symmetry plane (at left lower corner of domain). As i see , some information of domain arrive here and after increse the density except of reflection of information.

Well, still, if you get a stagnation point (an unphysical one), you should check how the code sets the boundary conditions. Are they set twice at the point? Maybe there's a conflict, it sounds like you are over-constraining the flow there, e.g. what happens to the density in the symmetry BC routine?

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