[Josh]

Hi everyone -

The purpose of my current simulation is to demonstrate the backflow caused by the leading edge of a 3D airfoil. The backflow occurs along the side of the airfoil in the span-wise direction. A velocity profile above the airfoil should look somewhat (very crude drawing) like this:
http://picasaweb.google.com/lh/photo...eat=directlink

After creating my simulation, my velocity profile above the airfoil looks like this:
http://picasaweb.google.com/lh/photo...eat=directlink

Zooming in:
http://picasaweb.google.com/lh/photo...eat=directlink

You can see minor accounts of backflow. After further refinement:
http://picasaweb.google.com/lh/photo...eat=directlink

Zooming in:
http://picasaweb.google.com/lh/photo...eat=directlink

Although backflow is occurring, it is on a very minute scale. Here is a zoomed out picture demonstrating the plane I used to produce the above two pictures (the plane is in the top right corner):
http://picasaweb.google.com/lh/photo...eat=directlink

As shown, the plane, and thus the area of backflow, is tiny. The backflow should be conspicuous. Here are some important characteristics about my geometry, mesh, and setup.

Geometry

NACA 0012 airfoil cut out of 1 m length, 0.5 m width, at a 15 degree angle of attack, from a fluid domain of dimensions 5 m high, 2.5 m wide, and 15 m long:
http://picasaweb.google.com/lh/photo...eat=directlink

Note that the airfoil is split down its center as symmetry will be used later to produce the full geometry:
http://picasaweb.google.com/lh/photo...eat=directlink

Mesh

Default body spacing of 0.2 m:
http://picasaweb.google.com/lh/photo...eat=directlink

Line control along span-wise airfoil edge of 0.0075 m spacing and 0.2 m radius of influence:
http://picasaweb.google.com/lh/photo...eat=directlink

40 layers of inflation with expansion of 1.02, y+ = 1, Re = 1E7, with the airfoil as a boundary. Here is a photo showing the airfoil meshing:
http://picasaweb.google.com/lh/photo...eat=directlink

Setup

http://picasaweb.google.com/lh/photo...eat=directlink

Steady State analysis.

Inlet boundary with axial velocity of 650 m/s to produce a Reynolds number of approximately 1E7. Outlet boundary with 0 Pa relative pressure. No slip airfoil boundary. Symmetry on the lowest z coordinate face. Free slip boundaries elsewhere.

An SST turbulence model was used for this particular run, although the Omega Reynolds Stress model was also used for previous runs (but with very similar results).

An RMS convergence criteria of 1E-5 was used.

________________________________________

Does this simulation seem reasonable? I used the SST turbulence and Omega Reynolds Stress turbulence models because of their good approximations of flow separation and complex effects. Can anyone recommend a better model(s)? Is my Post analysis an effective way to produce qualitative backflow effects?

Here is my CCL file:
http://rapidshare.de/files/48090177/...onCCL.ccl.html

Thanks for any and all help!