Impinging jet noise reduction using non-circular jets

Balakrishnan, P.; Srinivasan, K.

doi:10.1016/j.apacoust.2018.08.016

Cited by 18 publications

(8 citation statements)

References 15 publications

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“…The launch vehicle is mainly affected by jet noise [1] and aerodynamic noise during flight [2], and the sound pressure level outside the cavity during the launch process can reach more than 170 dB [3]. The external noise of the rocket fairing which poses a threat to the safety of the internal payload is transmitted to the inside of the fairing through transmission and radiation in a wide frequency and random form.…”

Section: Introductionmentioning

confidence: 99%

Experiment-simulation Study on Noise Reduction of Cylinder Shell with Horn Helmholtz Resonator

Yan

et al. 2020

Teh. vjesn.

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This paper focuses on the noise reduction of the cylindrical structure at low frequency (130 Hz-180 Hz). The low-frequency noise response spectrum in the cylindrical cavity is obtained by using the Helmholtz resonator (HR) to reduce the noise peak amplitude. The acoustic simulation software Virtual.Lab is used to establish the finite element model of the cylindrical shell with HR, and to obtain the low-frequency acoustic response in the cylindrical cavity. The simulation model is validated by the experimental results. Then, the influence of installation position, the number of installed resonators and the resonators with different resonance frequencies in the cylindrical cavity are discussed. The results indicate that both the noise reduction band and peak amplitude are increased by installing the HR's on the cylinder shell. The noise reduction of the cylinder shell with HR installed on the upper position is larger than other situations. As the number of resonators increased, the frequency range of the noise reduction in the cylindrical cavity gradually increases, and the noise reduction of the cylinder cavity increases first and then decreases.

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Section: Introductionmentioning

confidence: 99%

Experiment-simulation Study on Noise Reduction of Cylinder Shell with Horn Helmholtz Resonator

Yan

et al. 2020

Teh. vjesn.

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“…The key features in designing multiple jet nozzles involve number of exits, exits spacing, exits total area, exterior and interior nozzle geometrics, shape of exits, and the plenum volume [4,10,11]. Principally, multiple jet nozzles with smaller outlet diameter is recommended for jet noise control.…”

Section: Introductionmentioning

confidence: 99%

“…Circular, elliptical, triangular, square, rectangular jet nozzles were investigated. In his research, noise spectrum was mostly studied in ultrasonic range and it was aimed to reduce ultrasonic noise [10].…”

Section: Introductionmentioning

confidence: 99%

The Acoustic Performance of 3D Printed Multiple Jet Nozzles with Different Conﬁgurations

Variani¹,

Dastamoz²,

Ahmadi³

2020

Sound&Vibration

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This work investigated multiple jet nozzles with various geometrical shape, number of exits, and material on reducing noise radiated from jet flows. Nozzles are categorized in two groups with few and many exit numbers, each with various exit shapes, slot and circular, and geometry. Firstly, nozzles are designed and then fabricated by a 3D printer, Form Labs, Form2USA, with polymeric resin. Also, the nozzle with the most noise reduction made of stainless steel. Noise and air thrust were measured at three air pressure gauges, 3, 5, 7 BAR and directions from nozzle apex, 30°, 90°, 135°. Nozzles with slot exit shape made of both plastic and stainless steel revealed the most noise reduction among all nozzles with few exit numbers, nearly 11-14 dB(A) and 11.5-15 dB(A), respectively. On average, slotted nozzle noise reduction was nearly 5-6 dB(A) more than finned nozzle. However, nozzles with more exit numbers, finned and finned-central exit, illustrated much more noise reduction than nozzles with few exit numbers, by almost 16-18 dB(A), they represented similar sound. All tested nozzles and open pipe demonstrated equal air thrust at each pressure gauges. The nozzles with slotted exit shape, either plastic or stainless steel, can provide reasonable noise reduction in comparison to other configuration with few exit numbers. In contrast, nozzles with more exit numbers demonstrated the most noise reduction.

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“…Impinging jets are directly relevant in applications such as spacecraft launches, gas turbine cooling, cold-spray technologies, aeroacoustics, thrust vectoring systems, among many others [1][2][3][4][5]. Depending on the velocities of the jets used, the resulting impinging flow phenomena can be very different, particularly between subsonic and supersonic jets [6,7].…”

Section: Introductionmentioning

confidence: 99%