Numerical Simulation Research On Aerodynamic Performance Of Pumping Of Windsurfing

Windsurfing is a high intelligent aquatic athletics that relates to meteorology,hydrology,oceanography,hydrodynamics,aerodynamics and so on. The development of Windsurfing's level not only requests athletes have rich experiences and skilled skills, but also profoundly understand and agilely use the pumping principium. So it is important to comprehend the aerodynamics and the pumping principium of windsurfing in order to increase the speed and competition result. It can also help to gain gold medals in sailing event of 2008 the Olympic Games.Pumping is the key technique in windsurfing. It is the sharp weapon that can be used to surpass the competitors,infects the competitors and keeps predominance. The theory that pumping can increase aerodynamic force of sail and speed is summarized from practical experience. There is no research about this aspect by and large. Traditional aerodynamics only pays attention to lift in the steady air, but it can not explain why pumping can increase the speed in the match. Luckily because of the quick development of Computational Fluid Dynamic, numerical simulation gradually becomes another important method of hydromechanics research.This paper discusses the basic actions and manners of pumping and obtains its aerodynamics characteristic through analyzing forces pressed on it. Based on many years research on pumping of windsurfing, combined the research of flapping of birds and insects, this study brings forward the pumping principium based on flapping theory, builds related mathematical models and describes the process of pumping reasonably. Pumping of windsurfing is a complicated 3D movement, so its simulation is a very complicated task. During the research process, this study uses the software Gambit to divide the gird and CFD software FLUENT to simulate the process of pumping dynamically with the aid of dynamic mesh model and User-Defined Function to divide the modes of motion., then obtain the pressure distribution pressed on sail,lift coefficient and drag coefficient during the motion. Meanwhile the state that the sail is not pumped is also be simulated. Through the contrast, this paper concludes that pumping can increase the lift coefficient and analyses aerodynamic performance of pumping of windsurfing.