关键词: 超声速混合层；凹腔；混合增强；自激振动；声学自激振荡

Abstract: In order to surmount the disadvantage that mixing enhancement induced by forced vibration cannot achieve easily in engineering application， a new technique that employing self-excited vibration splitter enhances mixing process was proposed. The design method for a splitter plate with certain band frequency is the key problem in this technique. The splitter plate with a cavity was employed in this paper and characteristics of self-excited vibration were analyzed systematically mainly through experimental study combing with numerical simulation. Results indicate that fluctuation of pressure resulting from acoustic self-oscillation of a cavity on the upper surface is the immediate cause of self-excited vibration. Factors such as constraint condition of the splitter plate， length depth ratio and ramp angle of the cavity play a significant role on characteristics of self-excited vibration. The frequency of self-excited vibration is inversely correlated with limit distance. Frequency grows sharply by 324.63% when limit distance is 0mm. It decreases by 19.36% at length depth ratio [K=7]comparing with [K=1].Besides， frequency of self-excited vibration and ramp angle of cavity have positive correlation and it increases by 23.15% at the angle of [90°].Changing constraint condition is a chief orientation to optimize splitter plate because it can obtain an outstanding increase in frequency.

Key words: Supersonic mixing layer；Cavity；Mixing enhancement；Self-excited vibration；Acoustics self-oscillation