Research On Local-turning Osculating Cones Design Method And Its Applications

Due to its outstanding aerodynamic performance,waverider is considered as one of the effective ways to break through the current "lift-to-drag barrier".It has become the research hotspot for hypersonic vehicle design.Among the waverider design methods,the osculating cone method has been widely used in the engineering application of waveriders thanks to its superiority.The osculating cone method has two basic assumptions in order to simplify the calculation process.One is that the shock angle inside each osculating plane must be constant and the other is to ignore the crossflow between osculating planes.These assumptions make the 3D flow can be simplified as a series of 2D flows,but also lead to the following drawbacks.The first drawback is that the shock is constrained to a sweep surface.The other drawback is that the accuracy of this method is comparatively low,and it is difficult to be used in the reversely design of shock waves with variable strength.To solve the aforementioned problems,the local-turning osculating cones method was proposed in this paper,where the influence of shock intensity and crossflows are taken into consideration.This method was applied to the design of waveriders and supersonic bump inlet.The principal work and remarks of this paper are as follow:(1)The domestic and international waverider design methods as well as their application progress in aerodynamic design were systematically summarized,which points out the direction for the future work of this paper.(2)The numerical simulation method and the corresponding boundary conditions were introduced.Simulations of three different supersonic examples were conducted to verify the accuracy of the numerical method,which provides the basis for the numerical simulation work in the following paper.(3)The multiple osculating cones method for variable intensity shock waves was proposed,based on the non-coaxial method of characteristics(NMOC).This method corrects the influence of shock intensity by introducing the streamwise curvature radius so as to overcome the limitation of the first assumption in the osculating cone method.Numerical results show that the multiple osculating cones method based on the NMOC could reproduce the shape of the shock wave and the flowfield accurately at different Mach numbers.And its accuracy was significantly higher than that of osculating cone method.(4)Combined with the non-coaxial method of characteristics,the local-turning osculating cones method(LTOCs)was further proposed,where the post-shock flowfield is discretized into a multitude of stream surfaces.By this way,the limitation of the second assumption in the osculating cone method can be overcome.The results demonstrate that the LTOCs method was able to solve the complex 3D flowfield with an error of less than 3%.The solution space of the LTOCs method is greatly improved compared with the conventional osculating cone method.(5)Based on the LTOCs method,three novel waverider design approaches,including variable cross-section shock waverider,multistage compression waverider and variable Mach number waverider,were proposed for the requirement of internal volume,compression performance and wide-speed range performance respectively.Numerical results demonstrated that all these approaches could meet the design requirements,and the design freedom of waveriders were expanded significantly with the utilization of 3D shock waves.(6)The general waverider design methods,such as osculating cone method and LTOCs method,were utilized in the design of the outer compression surface of supersonic bump inlet.The results show that the heterotypic bump breaks the convention of forward design for conical Bump,and liberates the limitation of lip shape and sweep angle,which is expected to greatly improve the comprehensive stealth performance of the aircraft.With the help of GUI tools in the Matlab environment,a heterotypic bump design platform was built to provide methods and tools for the next generation of advanced supersonic Bump inlet.In summary,starting with the flow characteristic of 3D shock waves,the limitations of two basic assumptions in the conventional osculating cone method were discussed in this paper.Subsequently,the local-turning osculating cones method was originally established to solve the complex 3D shock waves.Under the guidance of the LTOCs method,the design of waverider and supersonic bump inlet were carried out based on the 3D shock waves.The main aerodynamic performance and flow characteristics were obtained so as to lay the foundation for the development of the next generation of hypersonic waverider and the advanced supersonic Bump inlet in China.