超声速混合层在强迫振动下流场结构的实验研究

An Experimental Study on Flow Structure of a Supersonic Mixing Layer Influenced by Forced Vibration

关键词:  超声速  混合层  强迫振动  NPLS  流场结构

Key words:  Supersonic  Mixing layer  Forced vibration  NPLS  Flow structure

摘要:

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。

Abstract:

A vibrating controller system was adopted to excite the thin flat plate connected with the double-nozzle. The flow structure of supersonic mixing layer was presented by employing the nanoparticle-based planar laser scattering (NPLS) method. Through controlling the vibration of different frequencies and amplitudes and adopting edge detection technology，the generation and development of large scale structures in supersonic mixing layer were studied experimentally. The results show that forced vibration has an important effect on the flow structure and mixing efficiency. Compared with no vibration，forced vibration enhances three-dimensional characteristics and advances the instability position of mixing layer. Meanwhile，forced vibration promotes the mixing of upper and lower streams and enhances the mixing efficiency. With high frequency vibration，the growth rate of mixing layer increases by about 50%.