Acoustic and mixing characteristic of CD nozzle with inverted triangular tabs

ABSTRACTIn this paper, we study the pressure energy decay, acoustic and mixing characteristics of non-circular jet with inverted triangular tabs at different ranges of aspect ratio. The centre line pitot pressure profile of the inverted triangular tab and ordinary tab shows that the decay of the jet from elliptical jet with inverted tab is faster than the jet from circular jet. When the aspect ratio of nozzle increased, the core length of the jet changes significantly due to the pressure loss. At different aspect ratios, the shock structure shows a prominent change with respect to the mixing promotion. The screech frequency of the jet noise gives appreciable change as the nozzle pressure is increased, and nearly 20–30% of decrease is witnessed in the magnitude of screech frequency. Introduction of inverted triangular tab jet modifies the shock cell formation which extensively changes the screech amplitude due to axis switching.