Journal ArticleDOI
Effect of impingement surface roughness on the noise from impinging jets
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In this paper, the effects of roughness of the impingement plate widens the staging region of noise and the effect of nozzle-to-plate spacing distance and nozzle pressure ratio are investigated.Abstract:
This paper presents extensive acoustic measurements on jets impinging on surfaces of various surface roughness values. Besides surface roughness, the effects of nozzle-to-plate spacing distance and nozzle pressure ratio are also investigated. Turbulent mixing noise and tonal noise are explained using far-field wall-jet velocity and impingement region temperature fields. The results demonstrate that roughness of the impingement plate widens the staging region of impingement noise. In general, high speed jet impinging on a rough plate generates less noise compared to a smooth plate. When tones are removed from the spectra, it is found that acoustic power monotonically decreases with increasing surface roughness. Thermal imaging in the stagnation region indicates that whenever tones are present, the temperature at the stagnation region is high. Further, sound pressure directivity pattern of impingement noise is constructed by superimposing a wall-jet and a free jet in the appropriate orientations.read more
Citations
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Journal ArticleDOI
Noise characteristics and flow field of an impinging jet on a conical obstacle
Journal ArticleDOI
Experimental Characterization and Control of an Impinging Jet Issued from a Rocket Nozzle
TL;DR: In this paper, the authors present an experimental study of a jet is tested in the presence of high structural loads on the launch surface and the rocket components along with elevated noise levels.
Journal ArticleDOI
Cone angle effects on noise characteristics of jets impinging on conical obstacles
TL;DR: In this paper, an acoustic measurement experiment was conducted to investigate noise characteristics of jets impinging on conical obstacles of different cone angles, and the effects of impinging velocity and impinging distance were also studied.
Proceedings ArticleDOI
Flowfield and Noise Characteristics of Supersonic Rectangular Impinging Jet
TL;DR: In this paper , the authors examined the flowfield and noise characteristics of a supersonic rectangular jet issuing from an ideally expanded Mach 1.44 nozzle on the surface normal to the jet axis.
References
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TL;DR: In this paper, a theory for estimating the sound radiated from a fluid flow, with rigid boundaries, which as a result of instability contains regular fluctuations or turbulence is initiated, based on the equations of motion of a gas.
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On the Mechanism of Choked Jet Noise
TL;DR: In this paper, the authors examined the noise in two-dimensional flow with the aid of a dynamic Schlieren apparatus, verifying the suggested mechanism and showing the similarity to axially symmetric flow where discontinuities in frequency, partly analogous to edge tones, occur.
Journal ArticleDOI
A study of free jet impingement. Part 1. Mean properties of free and impinging jets
TL;DR: In this article, the mean properties of the flow field are established for three types of jet flow issuing from a circular convergent nozzle, and measured distributions of surface pressure are given which result when the jets impinge both normally and obliquely at various distances on several surface shapes.
Journal ArticleDOI
Dynamics of an impinging jet. Part 1. The feedback phenomenon
Chih-Ming Ho,N. Nosseir +1 more
TL;DR: In this paper, the authors show that a feedback mechanism is responsible for the sudden change observed in the pressure fluctuations at the onset of resonance in a high-speed subsonic jet impinging on a flat plate.
Journal ArticleDOI
Flow field and noise characteristics of a supersonic impinging jet
TL;DR: In this paper, the authors examined the flow and acoustic characteristics of an axisymmetric supersonic jet issuing from a Mach 1.5 converging-diverging (C-D) nozzle and impinging on a ground plane.