Application of Omega vortex identification method in cavity buffeting noise

Yanghui, Zhang; Hu, Xianliang; Lan, Wei; Liu, Yichen; Wang, Mo; Wang, Jingyu

doi:10.1007/s42241-021-0034-8

Cited by 11 publications

(5 citation statements)

References 20 publications

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“…Zhang et al (2021) used the Ω method for large vortex simulation of cavity dither noise and captured the process of vortex generation, development, collision, and fragmentation, confirming that the generation of cavity dither noise results in free shear layer oscillation and periodic vortex shedding. Additionally, several scholars have utilized vortex identification techniques in various fields based on different vortex identification methods.…”

Section: Introductionmentioning

confidence: 95%

“…It has a wide range of applications in vortex identification, particularly in turbulence research, where it can be used to reveal important properties such as vortex structure, turbulent energy transfer, and turbulence scale in turbulent flows. Zhang et al (2021) Due to the local constriction of the bottom holes and vertical joints of the water flow velocity difference to guide the water flow to form a vortex, the pool chamber has a significant three-dimensional water flow structure (Dong et al, 2022), and the vortex structure inside the fishway is closely related to its effect on the passing of fish.…”

mentioning

confidence: 99%

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Turbulent structural analysis of the combined fishway with vertical seam and bottom hole

Shen,

Chen,

Shi

et al. 2024

River Research & Apps

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The three‐dimensional flow velocities within the typical pool chamber of the rectangular fishway were measured in a vertical slit bottom‐hole combination fishway by a hydraulic model test using an acoustic Doppler velocimeter (ADV). This was aimed to analyze the effect of eddy structures within the pool chamber of the fishway on fish migration. Based on this, a numerical simulation study was conducted using the Reynolds mean model (RNG k‐ε) and large eddy simulation (LES). Additionally, the omega (Ω) eddy identification method was used to identify the eddy structure within the pool chamber of the fishway and dissect the flow characteristics of the water body within the pool chamber. The findings revealed that longitudinal flow velocity dominated the flow in the lower bottom layer of the pond. Moreover, the flow in the middle and upper layers was more turbulent and there is a phenomenon of backflow upstream, and the flow at the orifice was a divergent jet with the main flow slightly to the right bank, forming two vortices in opposite directions on both sides of the orifice. The fish passage mainly displayed the turbulent vortex structure, which can effectively slow down the water flow and provide a resting place for migratory fish. The vortex identification method can more accurately identify the vortex structure inside the flow field.

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Section: Introductionmentioning

confidence: 95%

mentioning

confidence: 99%

Turbulent structural analysis of the combined fishway with vertical seam and bottom hole

Shen,

Chen,

Shi

et al. 2024

River Research & Apps

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show abstract

“…These findings are consistent with previous research indicating that the closer the R pp to 0.0, the greater the noise reduction effect. 20,23 Shear layer Many studies 9,10 have shown that the shear layer has a significant impact on wind buffeting noise. Therefore, the timeaveraged velocity is shown in Figure 10.…”

Section: Spanwise Pressure Correlationmentioning

confidence: 99%

“…Many studies 9,10 have shown that the shear layer has a significant impact on wind buffeting noise. Therefore, the time-averaged velocity is shown in Figure 10.…”

Section: Wind Buffeting Noise Reduction Mechanismmentioning

confidence: 99%

“…5 Therefore, passive control methods such as deflectors, 6 sub-cavities, 7 leading-edge shapes, 8 etc., are still widely used. For example, Wang et al 9 and Zhang et al 10 improved the leading-edge shapes to increase the thickness of the boundary layer at the leading edge, resulting in a reduction of cavity noise by more than 10 dB. Li et al 11 achieved a reduction of wind buffeting noise by more than 10 dB by minimizing the interference between the shear layer and the recirculation in the cavity using a porous floor.…”

Section: Introductionmentioning

confidence: 99%

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Exploring the suppression mechanism of wind buffeting noise with bionic structures featuring leading-edge serrations and surface ridges

Cao

Zhang

et al. 2023

Journal of Low Frequency Noise, Vibration and Active Control

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The aim of this study is to investigate the effectiveness and mechanism of wind buffeting noise suppression using a new bionic structure inspired by the quiet flight of owls. Firstly, the new bionic schemes based on NACA0012 wing with two sinusoidal leading-edge serrations and one straight leading-edge curve are used in a cavity after verifying the simulation. Then, the results of the three bionic schemes are compared and analyzed. It is found that the schemes with leading-edge serrations and surface ridges can suppress wind buffeting noise effectively. In particular, the sinusoidal scheme with a wavelength λ = 0.24 c (chord length c) can significantly reduce resonance energies above 21 dB over a wide range of speeds. Furthermore, the study reveals that in the bionic scheme, only the negative pressure core moves in the opening and hits the trailing edge, which reduces the pressure fluctuation in the cavity. The boundary layer thickness (BLT) also fluctuates in span under the influence of the leading-edge serration and the surface ridge, which is favorable for suppressing wind buffeting noise. However, the suppression effect is not solely related to the fluctuation of BLT in the span at the trailing edge but is also influenced by the minimum BLT at this point. Therefore, if the BLT has a certain intensity fluctuation in the span, and the minimum BLT at the trailing edge is close to that of the smooth airfoil scheme, the noise suppression effect is significant.

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Application of Omega Identification Method in the Ventilated Cavities Around a Surface-piercing Hydrofoil

Zhi¹,

Qiu

Huang

et al. 2023

Springer Proceedings in Physics

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Application of Omega vortex identification method in cavity buffeting noise

Cited by 11 publications

References 20 publications

Turbulent structural analysis of the combined fishway with vertical seam and bottom hole

Turbulent structural analysis of the combined fishway with vertical seam and bottom hole

Exploring the suppression mechanism of wind buffeting noise with bionic structures featuring leading-edge serrations and surface ridges

Application of Omega Identification Method in the Ventilated Cavities Around a Surface-piercing Hydrofoil

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