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-   -   Boundary conditions for external flows (https://www.cfd-online.com/Forums/openfoam-solving/58884-boundary-conditions-external-flows.html)

ryan_m May 18, 2008 23:33

Hi, Im running 3D airfoils
 
Hi,

Im running 3D airfoils (NACA 0016 @ 0 degrees) using an incompressible solver (simpleFoam). The results Im getting aren't making much sense: non-symmetrical pressure distribution, the velocity at the inlet seems to be different to what I specified. I think my boundary conditions are at fault. Could someone please have a look at the following boundary conditions to see if there are any errors:

Pressure: fixedValue outlet, zeroGradient elsewhere

Velocity: fixedValue inlet, zeroGradient outlet, movingWallVelocity on boundaries and 0 at the airfoil walls

k, epsilon, nuTilda: fixedValue inlet, zeroGradient elesewhere

Any help will be much appreciated.

Ryan

ngj May 19, 2008 07:41

Hi Ryan The movingWallVeloc
 
Hi Ryan

The movingWallVelocity, is that on the side walls parallel to the longitudinal direction of the channel? I would put a symmetry condition on those walls, see e.g. User Guide sec 6.2.1.

The other boundary conditions look reasonable.

- Niels

ryan_m May 19, 2008 08:18

Hi Niels, I do have a symme
 
Hi Niels,

I do have a symmetry plane in the mesh which I defined as a symmetryPlane (forgot to mention that in original post!). The movingWallVelocity is for the top, bottom and side of my domain. I am currently running the case now, Ill post another comment if my results dont work out.

Thanks for your comments.

Ryan

pbo May 19, 2008 09:49

Hi Ryan, movingWallVelocity
 
Hi Ryan,

movingWallVelocity is for moving/deforming boundaries;
for a static mesh, used fixedValue for the Velocity at the top, bottom and side boundaries if what you want is to prescribe the velocity on these patches.
However, you will be better off using the slip condition on those.

Patrick


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