钝头飞行器高超声速侧向喷流干扰流场特性研究

The Study of Hypersonic Interaction Flowfield around a Blunt Vehicle with a Side jet

采用数值模拟方法求解N-S方程,对高超声速钝头飞行器绕流与侧向喷流干扰流场中的流动分离和旋涡特性,及其对喷流干扰区压力分布的影响进行了研究。在中小攻角时喷口前存在干扰引起的主分离涡和二次分离涡,喷口前拐角处还存在另一个调和主分离和喷流的第三个马蹄涡,大攻角时这三个马蹄涡消失,干扰规律与中小攻角不同;表面流谱中小攻角时为典型的双分离线和双再附线结构,主分离和二次分离为典型的闭形分离,大攻角时主分离非常靠前,且为鞍、节点结合的开式分离结构,干扰区内的分离为横向分离流动;不同的干扰流场结构导致中小攻角时主分离激波和喷流弓形激波在压力分布产生两个峰值,主分离马蹄涡和喷口前拐角处马蹄涡则产生两个波谷,随攻角增大分离区扩大,波峰和波谷都前移,峰值下降,大攻角时喷口前马蹄涡消失,压力波谷也消失,实验压力分布也从某种程度上验证了大攻角干扰流场特性与中小攻角差别的合理性。研究表明,在不同的攻角状态下高超声速钝头飞行器绕流与侧向喷流干扰流场分离和旋涡特性有很大的差别,引起喷流干扰区压力分布的明显不同,必然导致对喷流控制效率的严重影响。

In the present paper, the separation characteristic and vortex structures in the hypersonic interaction flowfields around a blunt vehicle with a side jet and their effect on interaction pressure distributions were studied using numerical method. The interaction between the jet flow and the flow around the body results in a main separated horseshoe vortex and a secondary horseshoe vortex before the jet at low angles of attack. A third horseshoe vortex can also be seen between the main and the second vortex. At large angles of attack, the third horseshoe vortex disappears. The interaction characteristics at large angles of attack are different from those at low angles of attack. The surface streamlines show the pattern of double separated lines and double attached lines at low angles of attack ; the main and the second vortex are typical close type separations. At large angles of attack, the main vortex moves ahead and becomes an open type separation; the separation in interaction region is also an open type structure. The main shock wave and the jet bow shock wave cause two high pressure peaks, while the main and the second horseshoe vortex cause two low pressure peaks. With the increasing of the angle of attack, the separation region spreads out; the high and low pressure peaks move ahead; and the peak value declines. At large angles of attack, the low pressure peak disappears with the disappearance of the third horseshoe vortex. The experimental pressure distributions verify the difference of interaction characteristics between low and large angles of attack. These differences in separation characteristic, vortex structures and interaction pressure distributions must affect the control efficiency of side jet seriously.