Numerical study of the acoustic spectrum of bubble clusters DOI Creative Commons
Fuqiang Deng, Di Zhao,

Linxin Zhang

и другие.

Research Square (Research Square), Год журнала: 2024, Номер unknown

Опубликована: Март 11, 2024

Abstract This study delved into the acoustic spectrum of bubble clusters, each consisting 352 vapor bubbles across volume fractions ranging from 0.005–40%. The organized in five distinct layers, were modeled using Volume Fluid (VOF) method to capture interfaces, and Ffowcs Williams-Hawkings (FW-H) methodology compute far-field pressure collapse. Further analysis revealed sound behaviors different fractions: For 25%-40%, time-domain shows that peak pulses two innermost layers are significantly higher than those outer layers. In frequency domain, octave decay rate levels is relatively low, around − 3dB/octave. 0.5%-25%, four with similar widths values observed time domain. there three peaks levels(SPL), directly linked difference collapse times within cluster, accelerates as fraction decreases, stabilizing at -6dB/octave when reduced 17.5%. 0.005%-0.5%, decreases 0.5–0.1%, number reduces. Below 0.1% fraction, only a single wider pulse observed. gradually increases decreasing exceeding 10dB/octave it drops below 0.1%, reaching up -11.7dB/octave.

Язык: Английский

Acoustic radiation of bubble clusters with different volume fractions DOI
Fuqiang Deng, Di Zhao, Lingxin Zhang

и другие.

Physics of Fluids, Год журнала: 2024, Номер 36(3)

Опубликована: Март 1, 2024

Cavitation noise, mainly from bubble cluster collapse, is a primary source of noise in underwater equipment. This study aims to elucidate the acoustic characteristics clusters with varying volume fractions (0.002%–43%), thereby illuminating patterns generated during collapse. With direct numerical simulation (DNS) method, we simulate collapse containing 352 vapor bubbles. Far-field sound pressure was calculated by using Farassat 1 A integral solution Ffowcs Williams–Hawkings (FW–H) equation. The results show that when fraction greater than 20%, higher fraction, closer far-field radiated its equivalent (whose equal cluster), and 30%, basically same as bubble. Furthermore, less 1%, lower is, obtained through superposition single (each an initial radius within free field) clusters, 0.1%, clusters' pressures agree those superposition. reveals pattern providing theoretical basis for prediction cavitation noise.

Язык: Английский

Процитировано

8
Assessment of cavitation erosion on an asymmetric hydrofoil based on energy conversion via a multiscale approach DOI
Mingzhe Zhou, Ziyang Wang, Huaiyu Cheng

и другие.

International Journal of Multiphase Flow, Год журнала: 2024, Номер 176, С. 104820 - 104820

Опубликована: Апрель 10, 2024

Язык: Английский

Процитировано

5
Unsteady behavior of cloud cavitation and its induced shock waves: Part 2: Two-dimensional multiphase flow analysis DOI

Takahiro USHIOKU,

Hiroaki Yoshimura

Experimental and Computational Multiphase Flow, Год журнала: 2025, Номер unknown

Опубликована: Янв. 17, 2025

Язык: Английский

Процитировано

0
A comprehensive study of the impact pressure induced by a single cavitation bubble collapsing near a solid wall DOI
Di Zhao, Lingxin Zhang, Fuqiang Deng

и другие.

Physics of Fluids, Год журнала: 2024, Номер 36(7)

Опубликована: Июль 1, 2024

We conduct a comprehensive investigation into the wall impacts induced by single cavitation bubble collapsing near solid wall, combining numerical simulations with theoretical analysis. classify modes of impact three categories based on standoff distance, γ: pressure wave impact, jet stagnation and water hammer impact. Our findings reveal that remains unaffected initial radius R0 bubble, exhibits proportional relationship square root driving Δp, inversely correlates γ. then derive expression for drawing insights from energy conversion principles. The other hand, is directly to Δp as well polynomial involving By quantifying velocity its formation mechanism, we obtain expressions both impacts. In accordance specific ranges occurrence magnitude distribution each type propose ultimate prediction model. When γ>1.97, predominant source maximum attributed reaching magnitudes 106 Pa. For γ values ranging 1.73 1.97, principal contributor shifts levels 107 Conversely, when γ≤1.73, cause effect, 108 This study provides novel perspective analyzing mechanics during collapse surface, developed models offer valuable predicting mitigating erosion.

Язык: Английский

Процитировано

2
A discontinuous cavitation model (DCM) DOI
Jun Zheng,

Yuanyuan Gu,

Yingjie Wei

и другие.

Physics of Fluids, Год журнала: 2024, Номер 36(8)

Опубликована: Авг. 1, 2024

A discontinuous cavitation model (DCM) containing the effects of ambient overpressure, incondensable gas, inertia, viscosity, surface tension, characteristic nuclei size, and speed was proposed based on two approximate local first integrals Rayleigh–Plesset equation. Discontinuities caused by sudden bursting, heterogeneous distribution, bubble-induced turbulence can, thus, be roughly represented. It employed in simulating kinds flows. presented more physical reasonability than Singhal (SM) capturing vigorous vaporization water pool under strong negative pressure. As for hydrodynamic around National Advisory Committee Aeronautics hydrofoil NACA0015, not only large-scale features were obtained as well SM, but also, some small-scale structures cloud presented. For instance, isolated bubbles their dynamic behaviors, such inception collapse, expansion shrinkage, breakup coalescence, captured. Extra pulsation, which is correlated with temporal–spatial distribution vapor concentration, can also observed cloud. Moreover, different from vorticity field DCM becomes a thick vortex sheet. another simulation case number 0.32 further confirmed its adaptivity supercavitation Furthermore, adjusting parameters (i.e., fluid density phase change layer near nucleus) DCM, oscillations waves excited fierce clouds.

Язык: Английский

Процитировано

2
Influence of distribution parameters on acoustic radiation from bubble clusters DOI Creative Commons
Fuqiang Deng, Lingxin Zhang, Peng Wang

и другие.

Ultrasonics Sonochemistry, Год журнала: 2024, Номер unknown, С. 107066 - 107066

Опубликована: Сен. 1, 2024

Язык: Английский

Процитировано

1
Effect of distribution parameters on the noise spectrum of bubble clusters DOI
Fuqiang Deng, Lingxin Zhang, Di Zhao

и другие.

Physics of Fluids, Год журнала: 2024, Номер 36(8)

Опубликована: Авг. 1, 2024

This study explores the effects of bubble distribution parameters on noise spectrum clusters through direct numerical simulations across volume fractions from 0.005% to 40%. Three types cluster distributions were analyzed: layered (uniformly sized bubbles with positioning), random and lognormal (log-normally distributed sizes positioning). Using Ffowcs Williams–Hawkings (FW–H) method, we evaluated sound pressure levels clusters. We found that arrangement positions has little impact collapse times At greater than 0.5%, size also shows minimal effect times. However, when fraction is less gradually approach time largest in a free field. Noise analyses showed significantly influences spectra within range 0.5%–25%, but outside this range. Importantly, negligible spectrum, demonstrated by nearly identical level octave decay rates for at same fractions. consistency can be mathematically described fitting formula: rate (dB/octave) = 18.192 × α−0.047−16.264. These findings enhance our understanding varied provide new insights into mechanisms cavitation noise.

Язык: Английский

Процитировано

0
Numerical Simulation of Molten Steel Flow Field in a Ladle Induced by Low‐Frequency High‐Power Ultrasound DOI
Qing Guo, Min Chen, Lei Xu

и другие.

steel research international, Год журнала: 2024, Номер unknown

Опубликована: Авг. 31, 2024

To encourage the use of ultrasound in calcium treatment molten steel, this study utilizes volume‐of‐fluid (VOF) method combined with a mixture model to analyze distribution flow field steel when is applied. The effects low‐frequency, high‐power on pressure field, volume fraction cavitation bubbles, velocity distribution, and turbulence intensity are investigated. results reveal pattern alternating positive negative during each cycle, lowest measuring −9.63 × 104 Pa at 96 kW. bubbles concentrated intense area beneath ultrasonic probe, exhibiting maximum 2.50 10 −2 . axial peaks central axis, whereas radial negligible. increases from 0.36 m/s 48 kW 0.82 120 This trend mirrors highest 276 These findings provide theoretical basis for improve steel. outcomes numerical simulation closely align experimental results, substantiating their reliability through comparison published studies.

Язык: Английский

Процитировано

0
Numerical study of the acoustic spectrum of bubble clusters DOI
Fuqiang Deng, Di Zhao, Lingxin Zhang

и другие.

Journal of Hydrodynamics, Год журнала: 2024, Номер unknown

Опубликована: Авг. 30, 2024

Язык: Английский

Процитировано

0
Acoustic feature extraction of radiation pressure signal induced by bubble oscillation under dual-frequency acoustic excitation based on CEEMDAN and bubble entropy DOI Creative Commons

Xianjue Zheng,

Yuning Zhang, Yiming Li

и другие.

Deleted Journal, Год журнала: 2024, Номер 1(4)

Опубликована: Ноя. 4, 2024

Acoustic feature extraction of radiation pressure signals (RPSs) induced by bubble oscillations is a crucial task in the characterization properties underwater objects. In this article, to improve accuracy, complete ensemble empirical mode decomposition with adaptive noise (CEEMDAN) and entropy (BE) algorithms are combined extract effective acoustic components RPS. For verification, proposed scheme applied typical simulated RPS under dual-frequency excitation. Compared other methods, CEEMDAN can richer information from RPS, including accurate values for amplitude period oscillation. Furthermore, when become more complex, CEEMDAN–BE gives better evaluation results than schemes terms three indices. Under complex conditions, signal performances singular value decrease greatly, but retains its high efficiency, which further confirms effectiveness scheme.

Язык: Английский

Процитировано

0