Unsteady flow behaviors and noise source identification of a ducted orifice using detached-eddy simulation

Author:

Li Fuqi12ORCID,Wang Peng12ORCID,Liu Yingzheng12ORCID

Affiliation:

1. Key Lab of Education Ministry for Power Machinery and Engineering School of Mechanical Engineering, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240, China

2. Gas Turbine Research Institute, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai 200240, China

Abstract

In the present study, turbulent flow through a ducted orifice is numerically modeled using dynamic delayed detached-eddy simulations (dynamic delayed detached-eddy simulation) to clarify their unsteady flow behaviors and noise generation mechanisms. To this end, a total of four orifices with different thickness-to-diameter ratios ( t/ d = 0.5, 2, and 4) and porosities (orifice hole area to pipe area ratio, [Formula: see text] = 20% and 31%) were chosen for comparison at a Reynolds number of 10 000. Characteristics of the unsteady turbulent flow are first examined in terms of time-mean and statistical flow quantities as well as wall pressure fluctuations. Subsequently, the coherent flow structures in the form of wavepackets are effectively evaluated through spectral proper orthogonal decomposition (SPOD) analysis. The main noise sources are identified as alternatively energetic acoustic dipoles on the orifice's leading and trailing faces, dominated by the intermittent interaction between the unsteady flow and the orifice plate, particularly at the inner edges. Comparisons of different orifice thicknesses at the same porosity ([Formula: see text]  = 31%) showed that the noise source in the thin configuration ( t/ d = 0.5) is alternatively dominated by the shedding and flapping behaviors of the vortical structures in the low-frequency range, while Kelvin–Helmholtz-type wavepackets result from the Kelvin–Helmholtz shear layer instability at higher frequencies. For thicker configurations ( t/ d = 2 and 4), reattachment of the separated shear layer occurs within the orifice throat region; the resultant SPOD modes reveal double-wavepacket structures issuing from the leading and trailing edges, with distinctly different behaviors captured at higher frequencies. Furthermore, for the thin orifice ( t/ d = 0.5), similar flow structures are found with different porosities ([Formula: see text] = 20% and 31%), with intensified noise levels observed at the lower porosity.

Funder

National Natural Science Foundation of China

Publisher

AIP Publishing

Subject

Condensed Matter Physics,Fluid Flow and Transfer Processes,Mechanics of Materials,Computational Mechanics,Mechanical Engineering

Reference32 articles.

1. L. Roumen , “ Pressure fluctuations and acoustic force source term due to water flow through an orifice,” Master's thesis ( Eindhoven University of Technology, 2021).

2. Whistling of an orifice in a reverberating duct at low Mach number

3. The Sound Field in Fully Developed Turbulent Pipe Flow Due to Internal Flow Separation, Part I: Wall-Pressure Fluctuations

同舟云学术

1.学者识别学者识别

2.学术分析学术分析

3.人才评估人才评估

"同舟云学术"是以全球学者为主线,采集、加工和组织学术论文而形成的新型学术文献查询和分析系统,可以对全球学者进行文献检索和人才价值评估。用户可以通过关注某些学科领域的顶尖人物而持续追踪该领域的学科进展和研究前沿。经过近期的数据扩容,当前同舟云学术共收录了国内外主流学术期刊6万余种,收集的期刊论文及会议论文总量共计约1.5亿篇,并以每天添加12000余篇中外论文的速度递增。我们也可以为用户提供个性化、定制化的学者数据。欢迎来电咨询!咨询电话:010-8811{复制后删除}0370

www.globalauthorid.com

TOP

Copyright © 2019-2024 北京同舟云网络信息技术有限公司
京公网安备11010802033243号  京ICP备18003416号-3