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niavarani June 12, 2003 05:53

Panel method problem
 
Hi I have a problem in panel method. I have designed an airfoil with EPPLER code. Eppler gives me a cusp airfoil , but when I use panel method to analyze my eppler out put airfoil, I have problem in trailing edge and lower surface of it. Can panel method analyze cusp airfoil or it must be sharp?

Thanks


Martin Nilsson June 17, 2003 10:01

Re: Panel method problem
 
With a classical panel method (based on Smith-Hess for example) you cannot solve for an airfoil with a cusp since the matrix becomes nearly singular.

Even if you have a method for reformulating and then solving the resulting equations, the numerical solution from a low order panel method will be grossly inaccurate near the trailing edge. This was well recognized in the late sixties and early seventies and was known as the fish tail effect. Any proper book on panel methods will tell you this.

Martin


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