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COBEM 2019
25th International Congress of Mechanical Engineering
SCALING OF THE FAR FIELD PRESSURE OF IN-FLIGHT JETS SIMULATED WITH A OPEN JET WIND TUNNEL
Submission Author:
Anderson Proenca , Hampshire , United Kingdom
Co-Authors:
Anderson Proenca
Presenter: Anderson Proenca
doi://10.26678/ABCM.COBEM2019.COB2019-1287
Abstract
This paper presents an experimental investigation into the far pressure field of in-flight jets. The aim of this work is to evaluate the representativeness of finite flight-stream in comparison to the full-scale problem, that is, a jet exhausted from an aircraft engine during take-off phase. An open jet wind tunnel has been used to simulate forward flight effects on jet mixing noise. Presently, pressure measurements performed perpendicularly to the jet nozzle exit have been carried out. Analysis of the results suggests that the jet mixing noise scale well with the eighth power of the difference between the jet velocity and flight-stream speed. This is expected from the dimensional analysis of the governing equations (Lighthill’s acoustic analogy). The far field pressure is also in agreement with aerodynamic measurements performed in the jet flow using hot-wire anemometry - the turbulence intensity of jets under several flight-stream speeds is seen to collapse well with the velocity difference. A new campaign is been performed at the moment to investigate observer polar angles, θ, in the range 40^o ≤ θ ≤ 130^o. It is hoped that the experimental evidence presented in this paper will improve understanding of the advantages and limitations of using small-scale open jet wind tunnels to survey forward flight effects on jet noise.
Keywords
jet noise, Flight Simulation, wind tunnel tests., Aeroacoustics
