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通过可控振动系统激励双喷管后的薄平板,采用基于纳米粒子的平面激光散射技术(NPLS)观测超声速混合层流场结构。控制薄平板的频率和振幅,结合边缘检测技术研究了超声速混合层大尺度结构的发展和演化规律。实验结果表明:强迫振动对超声速混合层流场结构以及混合效率有重要的影响。与无振动相比,强迫振动增强了混合层的三维特性,混合层的失稳位置提前;同时,强迫振动促进了上下两层流动的掺混,高频振动下混合层增长速度提高约50%,有效增强了混合。
The controllable vibration system is used to excite thin slab after double nozzle, and the flow field structure of supersonic mixed layer is observed by planar laser light scattering (NPLS) method based on nanoparticle. The frequency and amplitude of thin slab are controlled. The development and evolution of the large-scale supersonic mixing layer structure are studied by the edge detection technique. The experimental results show that forced vibration has an important influence on the flow field structure and mixing efficiency of supersonic mixing layer. Compared with the non-vibration, the forced vibration enhanced the three-dimensional characteristics of the mixed layer, and the instability position of the mixed layer advanced earlier. At the same time, forced vibration promoted the mixing of the upper and lower layers. The growth rate of the mixed layer increased about 50% , Effectively enhance the mix.