Numerical Study Of The Pitching Motion Of Vehicles And The Rudder Control

The future campaign environment requires the new vehicles with the high maneuverability. When there is a rapid maneuver, the vehicles will encounter a big unsteady aerodynamic force and sluggish aerodynamic force, which may bring prodigious influence on flight performance and the control of the vehicles. To evaluate this influence, there is no way but only flight test technology. This technology has two main disadvantages: one is that it's difficult to establish the unsteady aerodynamic force model and to distinguish its characteristic; another is that it bears a high expense.To fit the need of the forecast in dynamic aerodynamic force, and to avoid fully using the flight test methods, much efforts have been done to develop Virtual Flight Test technology and Virtual Flight Numerical Simulation technology, which contains a integration of unsteady flow, movement of vehicle and rudder controlling.This thesis is focused on the study on the movement and the aerodynamic force characteristic under the rudder's control of a square cross-section missile. At first, the steady flow over misssile is studied, and the results show that the missile is static stability. When the missile is flying with the 4 degree attack angle, the attack angle will decrease to balance angle without control. With the help of the deflexion of the rudder, the missile's attack angle will increase to 8 degree. When the missile is at a 8 degree position, it has a velocity to make the attack angle keep increasing, with the help of the deflexion of the rudder, the attack angle of missile can be kept at 8 degree.The thesis is divided into five chapters as follows:The first chapter is the introduction, in which, the development of the Virtual Flight Test technology is reviewed.In the second chapter, the numerical methods for simulating unsteady flows are introduced, and the details about AUSM+-up scheme,LU-SGS algorithm and dual-time step methods are also presented.Validation for the AUSM+-up module is presented in chapter 3. The inviscid flow past a cylinder,transonic flow past a aerofoil, and supersonic flow over missile with the square cross-section are simulated, and a good agreement is obtained between the presnet results and the experimential and reference data. It shows that the AUSM+-up scheme possesses high resolution for shock capaturing and high effeciency.In the fourth chapter, the dynamic grid method developed by the author is presented at first, and its good quality for grid generation with large deformation is validated, this technique can keep the initial grid'quality well. Then, three movements cases for the missile with uncontrolled, controlled by the rudder to change the attack angle to a appointed position and controlled by the rudder to keep the attack angle are numerically simulated, and some useful results are obtained for missile control by rudder deflexion.The conclusion remarking are presented in the fifth chapter, and the future research work are also proposed.At last the references and acknowledgements are presented.