MULTI-OBJECTIVE OPTIMIZATION AND AERODYNAMIC PERFORMANCE ANALYSIS OF THE UPPER SURFACE FOR HYPERSONIC VEHICLES

To aim at analyzing the variation of the aerodynamic performance as well as the volume of hypersonic vehicles caused by the modification of the upper surface, a two-dimensional multi-objective optimization study is carried out by considering the design condition of flight Mach number 6.5, flight altitude 27 km, and 4? flight angle of attack. The CFD-embedded pareto genetic algorithm is used as the optimization driver. On the basis of 2D optimization results, several typical 3D configurations are generated, and a primary relationship between the aerodynamic performance and the volume is obtained by numerical simulation. The results show that the lift-to-drag ratio is approximately linear inverse proportion to the volume for both two-dimensional and three-dimensional configurations, though there are significant di erences between the 2D and 3D aerodynamic coe cient values. Moreover, the lift-to-drag ratio can only gain a little increment (about 0.36%) by adjusting the symmetrical profile shape of the upper surface when the volume is a constant, while the volume has a relatively large adjustable range (about 1.93%) under the condition of fixing the lift-to-drag ratio. Besides, the numerical results also demonstrate that the adjustment range of the pitch moment of the vehicle is about 5% by modifying the shape of the upper surface when the lift-to-drag ratio and the volume are all fixed simultaneously.