Experimental investigation on a cavity-step-actuated supersonic oscillating jet  

作　　者：Luo Xiaochen Sun Bo Wang Xiang'ang 

机构地区：[1]Department of Aerospace Engineering, Nanjing University of Science and Technology

出　　处：《Chinese Journal of Aeronautics》2017年第1期274-281,共8页中国航空学报（英文版）

基　　金：supported by a grant from the Natural Science Foundation of Jiangsu Province (No. BK20150781)

摘　　要：Wind tunnel testing is conducted at different back pressures in a vacuum-type wind tunnel for a novel supersonic fluidic oscillator which consists of a two-dimensional Laval nozzle, a rectangular cavity and a backward step, to obtain its characteristics and the conditions for jet oscillating. The experimental results show that periodic asymmetrical flipping of the supersonic jet appears over certain nozzle pressure ratio（NPR） range according to schlieren visualization and pressure fluctuations. The jet flipping appears only when the jet is over expanded. The normalized average amplitude of the lateral pressure difference acting on the roofs of the cavity and the step varies around 0.2 while the periodic flipping appears. The supersonic jet periodic flipping frequencies obtained from the experiments agree well with those from the modified Rossiter mode for cavity-step acoustic resonance, but further investigations are needed to discover the underlying mechanism for the jet flipping.Wind tunnel testing is conducted at different back pressures in a vacuum-type wind tunnel for a novel supersonic fluidic oscillator which consists of a two-dimensional Laval nozzle, a rectangular cavity and a backward step, to obtain its characteristics and the conditions for jet oscillating. The experimental results show that periodic asymmetrical flipping of the supersonic jet appears over certain nozzle pressure ratio（NPR） range according to schlieren visualization and pressure fluctuations. The jet flipping appears only when the jet is over expanded. The normalized average amplitude of the lateral pressure difference acting on the roofs of the cavity and the step varies around 0.2 while the periodic flipping appears. The supersonic jet periodic flipping frequencies obtained from the experiments agree well with those from the modified Rossiter mode for cavity-step acoustic resonance, but further investigations are needed to discover the underlying mechanism for the jet flipping.

关 键 词：Jet cavity interactions Jet flipping Oscillating jet Supersonic jet Wind runnel testing 

分 类 号：V211.74[航空宇航科学与技术—航空宇航推进理论与工程]