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wiqi July 24, 1998 17:11

information required
I want to know the method to calculate pressure,lift & drag coeficients if pressure distributions & velocity distributions on airfoil are found by FLUENT CODE.


John C. Chien July 24, 1998 20:52

Re: information required
I thought FLUENT Company should have already taken care of this basic question. The only reason why you are computing flow over an airfoil is to get the lift and the drag coefficients. Unfortunately, this seemingly simple question is going to be very difficult to answer. The lift and the drag coefficients are the global quantities, which can only be obtained accurately when the 1) wall pressure distribution on the surface of the airfoil and 2) skin friction distribution on the surface of the airfoil are both exact solutions. This should be a simple task of surface integration. The skin friction is related to the turbulence modeling in general and the mesh and the numerical schemes. In the case of an airfoil flow and a positive angle of attack, the lower surface flow is accerlating, and is easier to model. The upper rear surface flow is decelerating, the current turbulence models still have difficulties in handling this region correctly. ( as I always say, the commercial code is a black box, the best place to get an answer is the support engineer of the developer company.)

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