质量引射对边界层稳定性的影响

采用直接数值模拟（DNS）方法和线性稳定性理论(LST)研究了质量引射对马赫数为6的钝板边界层中第二模态扰动演化的影响。研究了质量引射及扰动的不同因素对扰动演化的影响,包括引射速度幅值、引射宽度、位置、组合以及体积流量。研究结果表明:质量引射对二维和三维扰动波都起不稳定作用,当引射位置接近扰动波中性曲线的下支界时,不稳定作用最明显;体积流量是决定质量引射对边界层作用的重要因素;当体积流量较小时,质量引射组合放置能起到单个质量引射叠加的效果;LST预测得到的N值修正与直接数值模拟的结果相近,可以定量地反映质量引射对边界层流动稳定性的影响。

Effect of mass ejection on boundary layers stability

The effect of the mass ejection on the evolution of the second-mode disturbances in a boundary layer of Mach number of 6 on a blunt plate was investigated by using direct numerical simulation (DNS) method and linear stability theory (LST). Different parameters of the mass ejection and disturbances, such as the ejection velocity, width, location, combination and volume flowrate, were considered. Results showed that: the mass ejection destabilized the two-dimensional and three-dimensional disturbance waves, and the effect was the strongest when the ejection position was close to the lower bound of the neutral curve of disturbances; the volume flowrate was an important factor to determine the effect on the evolution of disturbances; the combined mass ejection had the superposition effect when its volume flowrate was small; the value of N predicted by LST was close to the direct numerical simulation result, implying that LST can quantitatively determine the effect of the mass ejection on the stability of boundary layer.