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Old   September 18, 2009, 13:56
Default winglet analysis
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kumar
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I am Intended to do CFD analysis on wing with winglets using CFX. I have wind tunnel results. i need to match ,my CFD data to experimental results.

I generated a grid with Icem. I generated def file using CFX pre.

The inlet conditions , known are Dynamic Pressure and free steam mach number ans Reynolds number. I did not know the outlet conditions.

Initially i started CFD runs using Velocity magnitude as inlet and atmospheric pressure as outlet. Solution did not converged and failed after 30 iterations. Then I tried by changing outlet condition to static pressure(roughly took 0.95% inlet Ps). Here also i did not get luck. I tried with keeping opening boundary condition at the outlet. Still I did not get any luck.

Let any one can suggest me how to proceed further & what modifications I need to do for setup?
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Old   September 18, 2009, 14:51
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Ahmed
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Quote:
Originally Posted by cfd_lean View Post

I am Intended to do CFD analysis on wing with winglets using CFX. I have wind tunnel results. i need to match ,my CFD data to experimental results.

I generated a grid with Icem. I generated def file using CFX pre.

The inlet conditions , known are Dynamic Pressure and free steam mach number ans Reynolds number. I did not know the outlet conditions.

Initially i started CFD runs using Velocity magnitude as inlet and atmospheric pressure as outlet. Solution did not converged and failed after 30 iterations. Then I tried by changing outlet condition to static pressure(roughly took 0.95% inlet Ps). Here also i did not get luck. I tried with keeping opening boundary condition at the outlet. Still I did not get any luck.

Let any one can suggest me how to proceed further & what modifications I need to do for setup?
Nothing is known at the outlet, so you select the outlet BC as your B condition,
(gradients are equal zero).
The selection of boundary conditions is not a question of trial and error, but they have to represent the physical boundary conditions that exist in your simulation. Books on CFD will give you the physical and the mathematical meaning of each boundary condition, and if you look the Help system or manuals of the soft ware you are using you will find these definitions
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