斜激波入射V形钝前缘溢流口激波干扰研究

Investigation on the shock interactions between an incident shock and a plate with V-shaped blunt leading edge

针对内转式进气道溢流口这一关键部位所面临的三维复杂激波干扰问题,将溢流口提炼简化为V形钝前缘平板,采用激波风洞实验观测结合数值模拟的方法,研究了前体斜激波与V形钝前缘溢流口相对位置变化引起的激波干扰的演化规律。结果表明:由于V形钝前缘自身的激波干扰,其驻点前弓形激波的脱体距离较大,波后存在大范围的亚声速区。当斜激波入射在该弓形激波接近正激波的部分时,发生Edney第Ⅳa类激波干扰,该流动结构与V形钝前缘自身带来的三维激波干扰相互耦合,形成多处超声速射流区域;当斜激波入射在该弓形激波亚声速区的声速点附近时,呈现出不同于Edney第Ⅲ类激波干扰的波系结构;当斜激波入射在该弓形激波的超声速部分时,形成的波系结构与Edney第Ⅱ、Ⅵ类激波干扰类似。

The cowl lip of a hypersonic inward-turning inlet is a critical region due to the complicated three dimensional shock interactions.To reveal these shock interactions and the inherent mechanisms,a simplified model of a plate with a V-shaped blunt leading edge was proposed to simulate the main characteristics of the cowl lip flow.Experimental observations in a shock tunnel in conjunction with numerical simulations were conducted to examine variations of the relative position of a wedge-induced forebody shock and the cowl lip.The results show that the stand-off distance of the bow shock in front of the stagnation point is large(compared with the bow shock of a cylinder with the same radius),followed by a wide subsonic flow region behind the bow shock.When the oblique shock impinges on the near normal part of the bow shock,Edney typeⅣa shock interaction occurs.On this occasion,the interaction between the incident shock and the bow shock is coupled with the shock interactions induced by the three dimensional flow over the V-shaped blunt leading edge,causing several regions of supersonic jet.When the oblique shock impinges on the subsonic region near the sonic point of the bow shock,a type of shock interaction that is different from the classification of Edney typeⅢis shown.When the oblique shock intersects with the bow shock at the supersonic region,the shock interaction structures are similar to the shock structures of Edney typeⅡand typeⅥ.More attentions should be paid to the shock interaction problem of the V-shaped blunt leading edge cowl in the design of an inward-turning inlet.