Numerical Simulation Of The High Lift Airfoil

This paper describes some basic issues of airfoil completely, including the study methods, geometry parameters, aerodynamic parameters, and the relationships of geometry parameters with aerodynamic parameters, then introduces the mathematical and physical foundations and methods of airfoil numerical stimulation. First, NACA4412 original airfoil (i.e. prototype) model is numerical stimulated, and the numerical results are compared with the corresponding experimental data, which show that the conclusion drawn by this paper is reliable. Then, NACA4424 original airfoil model (i.e. prototype) and its modified models are also stimulated, which are designed so that the trailing edge of the prototype is thicken first, then a smooth curve is drawn from a certain chord distance form its leading edge to the T.E.. Results show that at all considered attack angles and flow speeds the lift-drag-ratios of the modified models are increased obviously. In addition, NACA4412 original airfoil model and its six versions of modified models (including various starting modification position, trail edge thickness, type of the smooth curve etc.) are stimulated, it is found that: the lift coefficient and lift-drag-ratio are enhanced at certain attack angles ,the maximum increase in lift-drag-ratio is about 200%, at the same time the drag coefficient maybe decreases too at a little attack angle. At last, a modified model with a sharp trail edge of NACA4412 is also stimulated, it reduces the drag of the airfoil significantly, improves the aerodynamic characteristics of the airfoil, however the applicable attack angle is little, so, further study is needed.