[pcasto]

Hi everyone,

I am trying to simulate steady flow over a NACA0012 airfoil at Mach number 0.2 and AOA 2 degrees and I'm having problems converging to the solution with icoFoam.

I'm using a structured C-mesh of dimensions (384x64) which can be seen here:
www.stanford.edu/~pcasto2/naca0012_visc/mesh.pdf

The utility checkMesh outputs the following:

-------------------------
Checking geometry...
Domain bounding box: (-14.5446 -16.6068 0) (18 16.6068 1)
Boundary openness (-1.78119e-18 1.88139e-17 4.27264e-16) OK.
***High aspect ratio cells found, Max aspect ratio: 74554.3, number of cells 7232
<<Writing 7232 cells with high aspect ratio to set highAspectRatioCells
Minumum face area = 1.5362e-08. Maximum face area = 3.57128. Face area magnitudes OK.
Min volume = 1.5362e-08. Max volume = 3.57128. Total volume = 938.87. Cell volumes OK.
Mesh non-orthogonality Max: 88.216 average: 9.60062
*Number of severely non-orthogonal faces: 252.
Non-orthogonality check OK.
<<Writing 252 non-orthogonal faces to set nonOrthoFaces
Face pyramids OK.
Max skewness = 0.186059 OK.
*Edges too small, min/max edge length = 1.90263e-05 2.79354, number too small: 3244
<<Writing 3884 points on short edges to set shortEdges
All angles in faces OK.
Face flatness (1 = flat, 0 = butterfly) : average = 1 min = 1
All face flatness OK.

Failed 1 mesh checks.

-----------------------------

So it seems to complain about the HAR cells but I would really like to be able to obtain a solution on this mesh...

Now my problem is the following: I can't get icoFoam to convergence properly. The pressure residual goes down to 4e-04 but stops decreasing after. (see convergence history at: www.stanford.edu/~pcasto2/naca0012_visc/p0_conv.pdf) The Cp distribution I obtain for this convergence level does not agree with results obtained with our flow solver. (www.stanford.edu/~pcasto2/naca0012_visc/cp_plot.pdf).

My boundary conditions are as follows:
INLET
p: zeroGradient, U: fixedValue (69.383 2.422 0)
OUTLET
p: fixedValue 100000, U: zeroGradient
WALL
p: zeroGradient, U: fixedValue (0 0 0)

I'm using the same schemes used with the cavity tutorial except that I set nNonOrthogonalCorrectors to 2. I also reduced my time step to 2e-07.

I'm fairly new to OpenFOAM so maybe I missed something really obvious but I would really appreciate if you could help me in getting a converged solution.