A Study of Screech Tone Noise of Supersonic Swirling Jets

Yu, Young-Kil; Chen, R.-H.

doi:10.1006/jsvi.1997.1027

Cited by 16 publications

(6 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The variable exhaust nozzle (Clamshell) could either close completely to reverse engine thrust or be only slightly closed to form a notch, thus squeezing the jet and altering the exit geometry. Note that apart from nozzle exit modi"cation, nozzle inlet geometry [138] and the presence of swirl [139] are factors that a!ect screech. In recent years, several researchers have manipulated the internal contour of jet nozzles cleverly for thrust vectoring, enhanced mixing, and noise reduction.…”

Section: Screech From Nozzles Of Nonuniform Exit Geometrymentioning

confidence: 99%

Supersonic Jet Screech: Half-Century From Powell to the Present

Raman

1999

Journal of Sound and Vibration

259

123

View full text Add to dashboard Cite

Section: Screech From Nozzles Of Nonuniform Exit Geometrymentioning

confidence: 99%

Supersonic Jet Screech: Half-Century From Powell to the Present

Raman

1999

Journal of Sound and Vibration

259

123

View full text Add to dashboard Cite

“…Fortunately, the angle of primary interest for blowdown noise applications and in the present study is 90-degrees, which is identically 90-degrees for both conventions. A number of strategies and devices have been proposed to help mitigate transonic jet noise, including the use of chevrons [18,19,21], bevels [15,17,23], fluidic inserts [14], corrugations and lobes [17,21,23], post nozzle fluid injection [5,6,10], tabs [15,20], the use of coflows [4,16,18], flexible filaments [2,7,13], post nozzle wires and meshes [12], flow swirling [1,24], nozzle plugs and porous nozzle inserts [11], and reflection surfaces [3,8,9]. Of these, for transonic jet speeds, the reflection surfaces have shown the capacity for the greatest noise reductions at observation angles of 90 degrees or greater, with Khan et al [8] achieving a best case OASPL reduction of approximately 24 dB.…”

Section: Introductionmentioning

confidence: 99%

Influence of a Hemispherical Noise Reduction Reflector on Transonic Jet Flows

Coombs¹,

Zander²,

Schembri³

2020

Australasian Fluid Mechanics Conference (AFMC)

View full text Add to dashboard Cite

High pressure gas venting operations, known as blowdowns, produce significant noise. The simplest means of reducing blowdown noise is to reduce the jet velocity, however, this is often infeasible and/or undesirable in practise. Therefore, the capacity to design devices which provide noise abatement without significantly influencing venting velocities, is of practical interest. One device which has shown some potential for noise abatement is a hemispherical noise reduction reflector, however the influence of these devices on the jet velocity is unknown. Therefore, the present study aims to experimentally investigate the influence of hemispherical noise reduction reflectors on transonic jet flows. Flow measurements found the addition of a reflector did not significantly influence the resulting jet, beyond a slight increase in jet spreading, and therefore a slight reduction in peak velocity as the jet dissipates downstream, attributed to reduced flow entrainment.

show abstract

“…The swirling jet noise was higher than the non-swirling jets, except at angles less than 40° from the jet axis. Yu et al (18) studied tangential injection swirling flows and observed that swirl flow reduce the shock cell spacing compared to non-swirling flows. A high subsonic co-axial jet of Mach 0.9 was simulated by Andersson et al (19) , who observed the high levels of turbulent kinetic energy in the secondary core outer shear layers, which lead to an increase in the sound pressure levels.…”

Section: Introductionmentioning

confidence: 99%

Pipe jet noise reduction using co-axial swirl pipe

Balakrishnan

Srinivasan

2017

Aeronaut. j.

View full text Add to dashboard Cite

The present experimental work highlights the acoustic far field and flow field characteristics of confined co-axial swirling pipe jets. Co-axial confinements with six vanes at angles of 0°, 20° and 40° are considered here. Two pipe lengths of L/D=0.5 and 2 are studied. The Mach numbers studied range from 0.85 to 1.83. An increase in the pipe length causes suppression of the transonic tones in non-swirl pipe jets. Swirl reduces the low frequency noise components and increases the high-frequency components compared to non-swirl jet. The broadband shock associated noise is mitigated by the swirl pipe jets. However, the screech tone is completely eliminated by the swirl pipe jets. Further, swirl pipe jets radiate low levels of noise at all the emission angles compared to non-swirl pipe jets, for both the pipe length cases at supersonic Mach numbers. Increase in the pipe length enhances the shock associated noise and OASPL for the non-swirl pipe jet. Centreline pitot survey and schlieren visualisation show a reduction in core length, reduction in the number of shock cells, weakening/destruction of the shock cells by the swirl pipe jets compared to the non-swirl pipe jets.

show abstract

A Study of Screech Tone Noise of Supersonic Swirling Jets

Cited by 16 publications

References 0 publications

Supersonic Jet Screech: Half-Century From Powell to the Present

Supersonic Jet Screech: Half-Century From Powell to the Present

Influence of a Hemispherical Noise Reduction Reflector on Transonic Jet Flows

Pipe jet noise reduction using co-axial swirl pipe

Contact Info

Product

Resources

About