Study on the Flow and Acoustic Characteristics of Submerged Exhaust Through a Lobed Nozzle

Miao, T C; Likhachev, Dmitriy S.; Liu, Jingting; Qin, Shijie; Wu, Dazhuan; Chu, Ning; Wang, Leqin

doi:10.1007/s40857-015-0027-2

Cited by 7 publications

(3 citation statements)

References 19 publications

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“…Some of the early attempts include those on elliptic and rectangular jets. These include some analytical (Crighton 1973), numerical (Morris 1988;Tam & Thies 1993;Baty & Morris 1995) and some relevant experimental studies focusing on the turbulence, mixing and acoustics of non-axisymmetric jets (Tam & Zaman 2000;Li et al 2002;Zaman et al 2003;Miao et al 2015;Li et al 2001Li et al , 2002Hu et al 2002). The analytical work of Crighton (1973) showed that separable solutions can be obtained for elliptic jets.…”

Section: Introductionmentioning

confidence: 99%

Temporal stability analysis of jets of lobed geometry

Lyu

Dowling

2018

J. Fluid Mech.

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A 2D temporal incompressible stability analysis is carried out for lobed jets. The jet base flow is assumed to be parallel and of a vortex-sheet type. The eigenfunctions of this simplified stability problem are expanded using the eigenfunctions of a round jet.The original problem is then formulated as an innovative matrix eigenvalue problem, which can be solved in a very robust and efficient manner. The results show that the lobed geometry changes both the convection velocity and temporal growth rate of the instability waves. However, different modes are affected differently. In particular, mode 0 is not sensitive to the geometry changes, while modes of higher-orders can be changed significantly. The changes become more pronounced as the number of lobes N and the penetration ratio ǫ increase. Moreover, the lobed geometry can cause a previously degenerate eigenvalue (λ n = λ −n ) to become non-degenerate (λ n = λ −n ) and lead to opposite changes to the stability characteristics of the corresponding symmetric (n) and antisymmetric (−n) modes. It is also shown that each eigen-mode changes its shape in response to the lobes of the vortex sheet, and the degeneracy of an eigenvalue occurs when the vortex sheet has more symmetric planes than the corresponding mode shape (including both symmetric and antisymmetric planes). The new approach developed in this paper can be used to study the stability characteristics of jets of other arbitrary geometries in a robust and efficient manner.

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Section: Introductionmentioning

confidence: 99%

Temporal stability analysis of jets of lobed geometry

Lyu

Dowling

2018

J. Fluid Mech.

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“…Gabard et al [8] studied the application of mixed representation and Galbrun equation for the generation of the aerodynamic noise, solving the aeroacoustic model by a hybrid finite element method. Miao et al [9] studied the flow and acoustic Characteristics of submerged exhaust through a lobed nozzle by experimental analysis. Zeng et al [10] observed the phenomenon of sound mutation in the control valve by continuously changing the pressure ratio, proposing that the sound mutation can be used as a simple way of determining ranges of core flow and annular flow.…”

Section: Introductionmentioning

confidence: 99%

Study on Aerodynamic Noise Numerical Simulation and Characteristics of Safety Valve Based on Dipole and Quadrupole

Hou

Pan

et al. 2020

Acoust Aust

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Aiming at the problem that it is difficult to accurately predict the aerodynamic noise in the safety valve exhaust process, a new numerical simulation method that comprehensively considers the dipole sources and the quadrupole sources is proposed. The RNG k-ε model is used to simulate the steady-state flow fields, LES numerical method is used to simulate the transient flow, and then the unsteady disturbances are used as source terms in the generalized FW-H solver incorporating the dipole and quadrupole terms to solve for the acoustic field. This simulation method is used to calculate the exhaust noise of the safety valve under six different operating conditions, the sound source characteristics of the exhaust noise of the safety valve are analyzed, and the safety valve exhaust test of different working conditions was carried out. The results show that the relative errors of total sound pressure level between simulation and test does not exceed 5% under different exhaust pressures and different opening heights of the safety valve flap. By comparing the total sound pressure level logarithmically superimposed with the total sound pressure level of the dipole and the quadrupole, the sound source characteristics of the aerodynamic noise of the safety valve are mainly dominated by the sound source of the quadrupole. As the opening height of the safety valve flap and exhaust pressure increase, the total sound pressure level of the safety valve exhaust noise increases, while the relative errors between the simulation results and test data decrease. The proposed simulation method can be accurately applied to the prediction of the safety valve exhaust noise, and the prediction accuracy of this simulation method also increases when the opening height of the safety valve flap and exhaust pressure increase.

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“…They found that the sound pressure level would increase with the gas production. Miao et al 27 studied the flow and acoustic characteristics of submerged exhaust through a lobed nozzle. They found that nozzle structure has important effect on the submerged exhaust noise.…”

Section: Introductionmentioning

confidence: 99%

The flow and acoustic characteristics of underwater gas jets from large vertical exhaust nozzles

Miao

Liu

Qin

et al. 2018

Journal of Low Frequency Noise, Vibration and Active Control

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The flow and acoustic characteristics of underwater gas jets exhausted from large vertical nozzles are experimentally investigated in this work with gas flow rates of 30-150 m 3 /h, nozzle widths of d ¼ 10 mm, 20 mm, 30 mm, and 40 mm. A high-speed digital video camera is used to examine bubble behavior and flow regimes. Sound pressure is measured by two hydrophones and recorded by a digital audio tape recorder. The audio and video signals are synchronized to find out the relationship between sound and gas behavior. Experimental results indicate that the general behavior of gas exhausted into water is of periodical necking and expansion. Sound pressure peaks are mostly excited by necking in two ways: pinch-off and redial expansion. Necking itself is a kind of low frequency behavior, corresponding to strong low frequency sounds. Moreover, necking can force the growing bubble to oscillate and emit broadband sound. As the gas velocity increases, necking would happen more frequently, and gas jets would grow into larger volume in shorter time, and then the sound radiated from the gas jets would have higher frequency and larger amplitude.

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Study on the Flow and Acoustic Characteristics of Submerged Exhaust Through a Lobed Nozzle

Cited by 7 publications

References 19 publications

Temporal stability analysis of jets of lobed geometry

Temporal stability analysis of jets of lobed geometry

Study on Aerodynamic Noise Numerical Simulation and Characteristics of Safety Valve Based on Dipole and Quadrupole

The flow and acoustic characteristics of underwater gas jets from large vertical exhaust nozzles

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