Confinement effects on regular–irregular transition in shock-wave–boundary-layer interactions
Confinement effects on regular–irregular transition in shock-wave–boundary-layer interactions
复制标题
冲击波-边界层相互作用中规则-不规则转变的限制效应
DOI：
10.1017/jfm.2018.537
复制
发表时间：
2018
影响因子：
3.7
通讯作者：
P. Bruce
中科院分区：
文献类型：
--
作者：
I. J. Grossman;P. Bruce
斜激波在马赫 2 流中以 $12^{\circ }$ 的流偏转角产生。观察到了隧道壁处产生的冲击波-边界层相互作用（SWBLI）。新型可移动冲击发生器允许 SWBLI 相对于下游膨胀风扇的位置发生变化。研究了SWBLI、膨胀风扇和风洞布置之间的关系。纹影摄影、表面油流可视化、粒子图像测速和高空间分辨率壁压力测量用于研究流动。据观察，激波发生器向下（朝向地板，因此朝向激波反射点）的流法线运动伴随着（1）激波引起的边界层分离的流向范围的增长，（2）激波引起的分离点向上游移动，而重新附着点保持几乎固定，（3）分离激波强度的增加和（4）规则和不规则（马赫）反射之间的过渡，而不增加入射 冲击强度。自由相互作用理论在定义分离激波角中的作用被考虑并表明与短流向范围内的当前测量结果一致。提出并推理了 SWBLI 表示，它解释了在入射冲击强度没有增加的情况下发生的分离冲击强度的明显增加。
An oblique shock wave is generated in a Mach 2 flow at a flow deflection angle of $12^{\circ }$ . The resulting shock-wave–boundary-layer interaction (SWBLI) at the tunnel wall is observed. A novel traversable shock generator allows the position of the SWBLI to be varied relative to a downstream expansion fan. The relationship between the SWBLI, the expansion fan and the wind tunnel arrangement is studied. Schlieren photography, surface oil flow visualisation, particle image velocimetry and high-spatial-resolution wall pressure measurements are used to investigate the flow. It is observed that stream-normal movement of the shock generator downwards (towards the floor and hence the point of shock reflection) is accompanied by (1) growth in the streamwise extent of the shock-induced boundary layer separation, (2) upstream movement of the shock-induced separation point while the reattachment point remains nearly fixed, (3) an increase in separation shock strength and (4) transition between regular and irregular (Mach) reflection without an increase in incident shock strength. The role of free interaction theory in defining the separation shock angle is considered and shown to be consistent with the present measurements over a short streamwise extent. An SWBLI representation is proposed and reasoned which explains the apparent increase in separation shock strength that occurs without an increase in incident shock strength.