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Old   October 28, 2009, 11:40
Default Surface Pressure Osciallation
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Matt
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I am simulating flow around a wind turbine blade section. The Reynolds number is quite high (3e6) and as such i am using a turbulent model. I am none too familiar with turbulence theories but have been using the k-omega with a turbulent kinetic energy calculated via k=(3/2)(Ti*U)^2 and specific dissipation from k/w<=Re .

I am searching for a steady state solution to compare with some experimental results. The simulation runs and converges fine and lift data is roughly 5% low compared to the experimental data. Where i'm having issues is on the surface pressure distributions. I'm getting some checker boarding on the top leading edge of the airfoil and i can't figure out why. Below is an element plot of the pressure contour and i have circle the checker boarding.



Here is a picture of my grid. I built the grid in such a way that for the first 1% of chord away from the airfoil i used a structured grid and then progressed to an unstructured grid. Also a closeup of the mesh near the airfoil. I am using a Y+ of about 14 here. I have tried from 20 down to 4 with the same oscillating surface pressure results.




Here is a plot of the surface pressure compared to the experimental data i have. You can see the squigles at the top leading edge of the airfoil.



Anyone have any ideas on how to get rid of these. I have read about the Rhie and Chow technique of discretization and i and assume fluent can use this. I must be using the wrong solver or have a parameter set wrong. Also this is an incompressible simulation.
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