Acoustics measurements of military-style supersonic beveled nozzle jets with interior corrugations

Abstract

Increasingly powerful and noisy military aircraft have generated the need for research leading to the development of supersonic jet noise reduction devices. The hot, high speed supersonic jets exhausting from military aircraft during takeoff present a most challenging problem. The present study extends prior research on two methods of noise reduction. The first is the internal nozzle corrugations pioneered by Seiner et al. and the second is the beveled exit plane explored most recently by Viswanathan. A novel research idea of creating fluidic corrugations similar to the nozzle corrugations has been initiated by Penn State. To further the understanding and analysis of the fluidic corrugations, the present study focuses on the flow field and acoustic field of nozzles with two, three, and six conventional, hardwalled corrugations. The effect of the combination of the internal corrugations with a beveled nozzle is explored. The results show that significant noise reductions of over 3 dB of the mixing noise and the broadband shock-associated noise can be achieved. The combination of the beveled nozzle and the internal nozzle corrugations showed that there is less azimuthal dependence of the acoustic field than for the purely beveled nozzle. The combination nozzle was shown to reduce the noise over a wider range of polar angles and operating conditions than either the purely beveled nozzle or the purely corrugated nozzle.

Sounds and acoustic emission-based early fault diagnosis of induction motor: A review study

“…139 That include, concrete, 140,141 plastics, 142–144 polymers, 145–147 ceramics, 148–150 pipelines, 151–153 pressure vessels, 154,155 storage tanks, 156–159 bridges, 160–162 aircraft, 163,164 bucket trucks, 165 wood, 166–168 fiberglass, 169–172 composites, 173–175 welding, 176–178 , tubes, 179 aerospace structures 180–182 and finally for military applications. 183–185 Figure 2 illustrates AE instrumentation chain.…”

Unsteady velocity measurements of model-scale supersonic exhaust jets in military-relevant configurations

“…A top-down view of the aeroacoustics facility is shown in Figure 1. Specific details on the facility configuration, operation, and acoustic data collection and processing may be found in Powers and McLaughlin 33 , Powers 34 and Hromisin et al. 35

Figure 1.Top-down view schematic of the Pennsylvania State University High Speed Jet Aeroacoustics Facility.

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