|Alternative Title||Study of Static and Dynamic Aerodynamic Characteristics of Hypersonic Gliding Vehicle|
|Thesis Advisor||盛宏至 ; 王发民|
|Place of Conferral||北京|
|Keyword||高超声速滑翔飞行器 乘波体 黏性干扰效应 真实气体效应 静稳定性 动态气动特性|
Hypersonic gliding vehicle is a new type of launch vehicle that has the capability of rapid long-range reach and maneuvering flight, and it can deliver a load precisely with a large range of velocity and altitude, which make it the research focus in the world’s military powers. Focusing on static and dynamic aerodynamic characteristics of hypersonic gliding vehicle, the key scientific problems such as aerodynamic configuration design, the influence of multi-physical effects at high altitude and dynamic aerodynamic characteristics are studied and discussed in this dissertation.
Firstly, a waverider configuration with high lift-to-drag ratio is designed by means of viscous optimization according to engineering constraints. Considering the requirements of thermal protection, effective volume and static staility, the waverider configuration is modified through engineering-oriented design, which can meet the static stability constraints of three directions along coordinate axis and still maintain good aerodynamic performance. By using CFD method, the influence of viscous interaction effects and real-gas effects on hypersonic gliding vehicles is studied, it is found that the expansion region at the end of the windward side has great effect on position of pressure center. The sensitivity of different aerodynamic parameters for each physical effects is acquired as a reference for configuration design and evaluation of aerodynamic performance.
An efficient and accurate hypersonic unsteady aerodynamic model is then developed (Viscous-corrected Local Piston Theory), which is based on local piston theory with viscous correction, and it can be used in strong viscous interaction conditions at high Mach number and high altitude. A semi-empirical relation for the determination of effective shape for this method is presented based on steady Navier-Stokes equations. Furthermore, a series of two-dimensional and three-dimensional numerical examples with various Mach numbers, angles of attack and operating altitudes for different shapes are provided to validate the accuracy of VLPT. This model can be used in analysis of dynamic aerodynamic characteristics easily and has much higher computational efficiency than unsteady Navier-Stokes equations, so it is valuable in engineering application.
The static derivatives and dynamic derivatives of single degree of freedom are derived from VLPT. Compared with unsteady Navier-Stokes predictions, it is found that the method of VLPT for calculating dynamic damping derivatives is reliable. By coupling the governing equations for free motion of flight vehicles (Lagrange’s equations) and hypersonic unsteady aerodynamic model, the nonlinear system for analysis of free disturbance movement at equilibrium point is established. Applying time-domain analysis in state space, the characteristic roots are obtained and the influence of longitudinal static derivatives and dynamic derivatives on pitching oscillation of hypersonic gliding vehicle is studied, which is validated through unsteady computational fluid dynamics simulation that is coupled to a rigid body dynamics simulation (CFD/RBD).
At the end of this dissertation, the analytical model for lateral and directional coupled motion is also established. After choosing a group of typical conditions in gliding trajectory, the root loci at different angles of attack for different motion models are obtained by means of time-domain analysis in state space. The root loci show that there are two unstable motion models in lateral and directional coupled motion: the spiral motion at small angle of attack and the Dutch roll movement at larger angle of attack. To validate these two unstable motion models, the coupled CFD/RBD method has been used, and then the unstable motions are studied based on variations of aerodynamic parameters. Moreover, some strategies are provided according to Hurwitz criterion for the purpose of improving the stability of lateral and directional coupled motion. The above results can be used as a valuable reference for control system design and further modification of hypersonic gliding vehicle.
|韩汉桥. 高超声速滑翔飞行器静/动态气动特性研究[D]. 北京. 中国科学院大学,2013.|
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