Large eddy simulations of a turbulent mixing layer periodically excited with fundamental and third harmonic frequency  

作　　者：Jörg SCHLÜTER Dan ZHAO Abhishek SARKAR 

机构地区：[1]School of Engineering,Deakin University,Waurn Ponds 3216,Australia [2]College of Engineering,University of Canterbury,Christchurch 8041,New Zealand [3]School of Mechanical and Aerospace Engineering,Nanyang Technological University,Singapore

出　　处：《Chinese Journal of Aeronautics》2023年第5期33-40,共8页中国航空学报（英文版）

基　　金：the financial support provided by the Deakin University,Australia;the University of Canterbury,New Zealand (No. 452DISDZ)

摘　　要：A better understanding of the mixing behavior of excited turbulent mixing layers is critical to a number of aerospace applications.Previous studies of excited turbulent mixing layers focused on single frequency excitation or the excitation with fundamental and its second harmonic frequency.There is a lack of detailed studies on applying low and higher frequency excitation.In this study,we have performed large-eddy simulations of periodically excited turbulent mixing layers.The excitation consists of a fundamental frequency and its third harmonic.We have used phase-averaging to identify the vortex structure and strength in the mixing layer,and we have studied the vortex dynamics.Two different vortex paring mechanisms are observed depending on the phase shift between the two excitation frequencies.The influence of these two mechanisms on the mixing of a passive scalar is also studied.It is found that exciting the mixing layer with these low and high frequencies has initially an adverse influence on the mixing process;however,it improves the mixing further downstream of the splitter plate with the excitation using a phase shift ofΔφ=πshowing the best mixing performance.The present works shed lights on the fundamental vortex dynamics,and has great potential for aeronautical,automotive and combustion engineering applications.

关 键 词：Flow control Flow excitation Large eddy simulations Turbulent mixing layer Vortex dynamics 

分 类 号：V211[航空宇航科学与技术—航空宇航推进理论与工程] V411