一种宽速域乘波体的设计及气动特性研究

为了解决乘波体偏离设计条件下气动特性会恶化，特别在低速时，升力严重不足这个问题，提出了通过增大后掠角生成前缘涡，增加背风面的升力，以改善乘波体低速气动性能.首先使用Visual Basic编程语言，并通过CATIA软件二次开发技术，实现了锥导乘波体的参数化设计和自动生成.再通过控制圆锥角和流场长度这两个设计参数，获得了大后掠乘波体构型.最后，运用剪切应力输运（shear-stress-transport，SST）模型，计算了所得乘波体的气动特性，并分析了流场变化，发现乘波体在设计状态下激波能很好附着在前缘上，在小的正攻角下，乘波体可获得比设计状态更高的升阻比，满足巡航要求.运用k-ω模型计算了乘波体的低速气动特性，得到了不同攻角下升力、阻力和升阻比的变化规律.研究结果发现，乘波体在低速下产生了明显的涡结构，在合适攻角下，能产生数量可观的附加升力，提高了乘波体的水平起降性能. 

Design and Aerodynamic Analysis of a Wide Speed Waverider

Aerodynamic characteristics of a waverider may be worsen under off-design conditions, especially lift is seriously insufficient at a low speed. It was proposed to improve the low-speed aerodynamic performance of waverider by increasing sweepback angle to generate leading edge vortex so as to increase the lift of leeward surface. Firstly, through CATIA software secondary development technology with the use of Visual Basic programming language, parametric design and automa-tic generation of cone-derived waverider were realized. Secondly, large sweepback waverider configuration was obtained by controlling two design parameters, namely, cone angle and flow field length. Finally, through calculating the aerodynamic characteristics via SST model and analyzing changes of flow field, it was found that shock waves can be well attached to the leading edge under the design condition. Moreover, compared with the design state, the waverider could reach a higher lift-drag ratio with a small positive angle of attack (AoA), which could satisfy cruising requirements. The variation regularity of lift, drag and lift-drag ratio under different AoAs were found by calculating the low velocity aerodynamic characteristics of the waveriders with k-ω model. Result shows that the waverider produces obvious vortex structures at a low velocity, and it can also generate considerable additional lift under an appropriate AoA, which enhances the performance of horizontal takeoff and landing.