[Gmsh] High Order Boundary Layer issues in 2D

John Moore johnpmooreiv at gmail.com
Sat Feb 15 22:02:50 CET 2014


Hi All,


I've been beating the same problem around a bush for a while and was hoping
that one of you could point me in the right direction.

I have been trying to create a high order mesh in 2D with a boundary layer.
I am using the extrude command to explicitly create the boundary layer
surface, rather than using the "Boundary Layer" field. I have attached my
script as well as two images of my problems.

The two problems that I am having are:

1. When I extrude the upper and lower airfoil curves (my geometry lies in
the z=0 plane) the surface normals point in the wrong direction (into the
screen). I would like the normals to point out of the screen. I have tried
to change the orientation by prescribing a Physical Surface composed of the
extruded surfaces, but this doesn't work.

2. In order to generate the high-order mesh I first execute the
"FastCurving" algorithm followed by the "Optimization" algorithm. The fast
curving works fine, but when I apply optimization, the boundary layer near
the leading edge becomes invalid. When this happens I get the following
terminal message:

DBGTT: no normal edge

I think the issue has something to do with when the extrusion tries to
combine the upper and lower splines. I know I could probably fix the issue
by composing the airfoil surface of a single spline, but I would like a
better solution than that.

Are there work-arounds for these issues?

Any help would be great! Thank you for your time.

John
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