| At designing and modernization of space vehicle it is required accurate and reliable data on the flow field, aerodynamic characteristics, heat transfer processes. Taking into account the wide range of flow conditions, realized at hypersonic flight of the vehicle in the atmosphere, it leads to the need to incorporate in employed theoretical models the effects of rarefaction, viscous-inviscid interaction, flow separation, laminar-turbulent transition and a variety of physical and chemical processes occurring in the gas phase and on the vehicle surface. Getting the necessary information through laboratory and flight experiments requires considerable expenses. In addition, the reproduction of hypersonic flight conditions at ground experimental facilities is in many cases impossible. As a result the theoretical simulation of hypersonic flow past a spacecraft is of great importance. Use of numerical calculations with their relatively small cost provides with highly informative flow data and gives an opportunity to reproduce a wide range of flow conditions, including the conditions that cannot be reached in ground experimental facilities.One of the main problems that arise at designing a spacecraft is the high convective heat fluxes (aerodynamic heating) to the vehicle surface at hypersonic flight. Taking into account the complexity of practical problems, an appropriate physical model and numerical techniques need to be verified. Temperature distribution of structure and flow and heat flux on the surface of projectile at various moments of aerodynamic heating problem of the hypersonic projectile with spherical head and cone body are simulated with ANSYS FLUENT, which is based on the theory of Computational Fluid Dynamics (CFD), on the platform of ANSYS Workbench. Problem of flow around circular cylinder in high temperature wind-tunnel experiment is studied, the quarter 2D cylindrical model is instead of the symmetrical model. The temperature and velocity distribution at time 2s,3s,4s and 5s was obtained. Compared with the experiment result, which presented a tiny error, confirming the accuracy of simulation this kind of aerodynamic heating problem with CFD methods.Panel flutter is a self-excited, dynamic-aeroelastic instability of thin plate or shell-like components of a vehicle. Aerothermoelastic behavior of skin panel with static/dynamic edge movability effect in hypersonic flow is researched. The aerothermoelastic governing equations are developed from the geometrically non-linear theory of infinitely long two dimensional curved panels. These equations are based on the third-order piston theory aerodynamic for modeling the flow-induced forces. Von Karman non-linear strain-displacement relation in conjunction with the Kirchhoff plate-hypothesis is adopted. A geometrically imperfect curved panel forced by a supersonic/hypersonic unsteady flow is numerically investigated using Galerkin approach. The results of the influence of the temperature in conjuction with the the themal degradation of thermomechanical properties of the material on flutter speed and flutter frequency shows that with the increase in the temperature amplitude, a decrease in flutter mach number and eigenfrequency is experienced. Furthermore, the effects of thermal degradation is also considered in this model. The results of the effect of thermal field as a function of curvature ratio reveal that (1) for large values of mass ratio, a decrease in the flutter speed is experienced; (2) with the effect of increasing the imperfection, a large reduction is exhibited in flutter speed.; (3) at relatively small values of curvature ratio, the panels characterized by larger thickness ratio exhibit and increase in flutter speed.The results of this thesis are accurate and credible, and have some reference value in the study of aerodynamic heating and aerothermoelastic of spacecrafts. |
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