匀速俯仰运动及角速率对横向喷流的影响

Uniform pitching motion and angular rate effects on transverse jet interaction

为研究运动对横向喷流干扰特性的影响,数值模拟了导弹模型匀速俯仰运动过程的超声速横向喷流,获取了运动状态下的横向喷流干扰量,并对比分析了俯仰运动和角速率对喷口附近流场结构、模型表面极限流线、表面压力分布和子午线压力变化及气动特性和干扰放大因子造成的影响。结果表明:模拟参数范围内,动态及角速率影响随运动方向及迎角范围而发生变化;中小迎角时主要影响上游分离区和尾部偏折效应,大迎角时弓形激波位置变化显著;俯仰运动的气动特性和横向喷流干扰特性出现动态迟滞,且随角速率增加而增强;动态大迎角下由于压力平台效应减弱,其力矩放大因子受俯仰运动影响更为明显,出现偏离静态的不利结果。

To investigate the effect of motion on transverse jet interaction,steady and unsteady numerical simulations are performed on a missile model at fixed angle of attack and with uniform pitching motion.To study the differences between steady and unsteady cases,this paper analyzes the characteristics of transverse jet interaction,including typical interaction flow topology in the vicinity of nozzle exit,streamlines and pressure distribution on model surface,pressure changes along centralline.The results show that the effect of pitching motion and its angular rate on flow topology,pressure platform,and rudder surface varies with the change of the motion direction and the range of angle of attack.At low and moderate angles,the effects are mainly in the upstream separation area and rear bending barrel shock,where as the location of bow shock wave changes significantly at high angle of attack.Unsteady hysteresis in aerodynamic characteristics and transverse jet interaction are induced by pitching motion and has been enhanced with an increasing pitch angular rate.The pitch moment amplification factor is influenced more significantly by motion during high angles than during low angles.