Type of Document	Thesis
Author	Yerapotina, Sandeep
URN	etd-09282005-201355
Title	Aeroacoustic Characteristics of Supersonic Twin Jets
Degree	Master of Science
Department	Mechanical Engineering, Department of
Advisory Committee	Advisor Name Title Krothapalli Anjaneyulu Committee Chair Farrukh Alvi Committee Member Namas Chandra Committee Member
Keywords	Twin Jets
Date of Defense	2005-09-16
Availability	unrestricted
Abstract An experimental study was conducted to examine the aeroacoustic characteristics of supersonic twin jets and compare them to a single jet of equivalent area. Axisymmetric converging diverging nozzles having a fully expanded Mach number of 1.76 were operated at overexpanded and ideally expanded conditions. Planar velocity field measurements were made using Particle Image Velocimetry (PIV) at cold operating conditions. The results obtained show a decrease in potential core length for the twin jets. The twin jets were found to merge earlier when they were canted. Lower turbulence levels were observed for the twin jets compared to a single jet. The turbulence in the inter nozzle region of the canted twin jets was significantly reduced due to increased jet interaction. Far-field noise measurements for the twin jets were made at two azimuthal angles and compared to a single jet of equivalent diameter. Noise measurements showed a reduction in OASPL for the twin jets at most of the polar angles measured, with a 2 dB reduction in peak radiation direction. The OASPL levels of the twin jets showed a strong dependence on the azimuthal angle. Broadband shock noise was observed to have shifted to higher frequencies. Acoustic shielding was observed at some sideline angles, which caused significant reduction in high frequency noise.
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