Modeling And Characteristic Analysis Of Hypersonic Vehicle

Hypersonic vehicle wide application prospect makes it an object of scientific research scholars eager to study. Now air-breathing hypersonic vehicle is widely applied. Whose unique aerodynamic shape, flight environment and cross-coupling effect of its internal components make modeling work quite complexly. Establishing a precise mathematical model is an urgent research tasks, analyzing characteristics of the aircraft can help scholars understand the hypersonic vehicle well, which is conducive to the follow-up study on the control method and control system design. So the works of modeling and characteristic analysis of hypersonic vehicle have a great significance.Based on oblique-shock and Prandtl-Meyer expansion theory, we use the geometry of nonlinear 3-DOF longitudinal dynamical model of a generic scramjet-powered hypersonic vehicle developed by Bolender which consider a first principle. Assuming its width is 20 ft, using the integrated modeling approach establishes six degrees of freedom aerodynamic models. Because of the scatter of the aerodynamic data, it's not easy to design nonlinear control systems. Therefore, in the using curve fitting based on aerodynamic data of 6DOF model obtained control-oriented curve fitting model.The natural flow will adhere to the surface of the hypersonic vehicle to prevent the aircraft forward and produce viscous friction during the flight, which are viscous effects. The viscous effects have a significant impact on drag. This paper establishes a viscous aerodynamic model, comparative studies the effects of viscous effects on characteristics of the aircraft, and shows the corresponding flight boundaries.The task of scramjet inlet is capturing airflow and supplying for the combustion to produce thrust, providing power for the entire aircraft, its performance is critical for aircraft. The article studies three cases about the effects of the translating cowl of inlet on capturing air mass flow, comparative study the effects of the translating cowl on characteristics and flight boundaries of the hypersonic vehicle.There are many uncertainties factor during hypersonic aircraft flying environmental, it's not realistic to analyze every factor. The paper uses the polynomial chaos theory to analysis the uncertainty of aerodynamic model, researches the impact of uncertain input on the system output and gives the correlation probability and statistics features of the output. Comparative study of the impact of uncertainty on the aerodynamic characteristics and sensitivity analysis of the uncertain parameters, provide theoretical support for the robustness of the control system design.