Study on Flow Characteristic of Sub-/Super-Sonic Mixing Layer

Jieli Wei,Yi Zhou,Yakun Huang,Guanji Gong,Xiaomin He

doi:10.1051/jnwpu/20203830649

Abstract

In order to obtain the flow characteristics of sub-super-sonic mixing layer including velocity distribution, pressure distribution and development of mixing layer, experimental and numerical investigations were conducted. PIV technique was employed to measure the two-dimensional velocity distribution in the experiment while the standard k-ω turbulent considering the effect of compressibility was adopted to simulate the flow characteristic of mixing layer. The Mach number of subsonic stream and supersonic one was 0.11 and 1.32, respectively. The results show the flow of mixing layer is temporally transient. The interface between two streams lies initially as an approximately line segment; afterward, it becomes wrinkled and distorted; finally, it breaks up. The mixing layer develops linearly along streamwise direction in the time averaged velocity field with a growth rate of 0.135. The velocity and total pressure distributions in the mixing layer are self-similar.

Highlights

PIV technique was employed to measure the two⁃dimensional velocity distribution in the experiment while the stand⁃ ard k⁃ω turbulent considering the effect of compressibility was adopted to simulate the flow characteristic of mixing layer
The results show the flow of mixing layer is temporally transient
The velocity and total pressure distributions in the mixing layer are self⁃similar

Summary

Introduction

口平均总压( kPa) 。混合层内,0 < Ur < 1,0 < prt 合层厚度发展。随着流向发展,混合层边界向两侧扩展,混合层厚度不断增加。 x = 10 ~ 100 mm 区间, 采用粒子图像测速技术 PIV 对亚-超声速混合层流场进行测量, 同时, 采用基于雷诺平均方程 RANS 的标准 k⁃ω 湍流模型开展稳态数值模拟,考虑亚超声速混合层压缩性影响,获得亚 -超混合层基本流场特征,包括速度分布、压力分布和混合层厚度发展。超声速气流马赫数 Ma1 为 1.32,亚声速气流马赫数 Ma2 为 0.11,混合层内静压约为 70 kPa。研究得到的主要结论如下: 1) 亚-超声速混合层具有非稳态特征,2 股流体分界面从近似线性分布,随后发生褶皱变形,最后发生破碎并出现离散的流体微团; 2) 混合层的时均特征为沿流向近似呈现线性增长,增长率为 0.135 mm / mm。 An Analytical and Experimental Study of the Plane, Incompressible, Turbulent Free⁃Shear Layer with Arbitrary Journal of Fluids Engineering, 1965, 87(2) : 421⁃428 Experimental Investigation of Spatiotemporal Structures of Supersonic Mixing Layer[ D] .

Results

Conclusion