Coaxial round water jet at velocity ratios close to unity, Part I: Mean and turbulent flow characteristics

IF 2.6 3区工程技术 Q2 ENGINEERING, MECHANICAL International Journal of Heat and Fluid Flow Pub Date : 2024-12-07 DOI:10.1016/j.ijheatfluidflow.2024.109650

D. Hasin , A. Mitra , R. van Hout

{"title":"Coaxial round water jet at velocity ratios close to unity, Part I: Mean and turbulent flow characteristics","authors":"D. Hasin , A. Mitra , R. van Hout","doi":"10.1016/j.ijheatfluidflow.2024.109650","DOIUrl":null,"url":null,"abstract":"<div><div>In this paper, planar time-resolved particle image velocimetry measurements are reported in the near-field of a coaxial jet at velocity ratios, <span><math><msub><mrow><mi>r</mi></mrow><mrow><mi>u</mi></mrow></msub></math></span> = 0.66, 1.0 and 1.32. At each <span><math><msub><mrow><mi>r</mi></mrow><mrow><mi>u</mi></mrow></msub></math></span>, at least two different Reynolds numbers, Re, were investigated. Spatial distributions of mean velocities, Reynolds stresses, vorticity and swirling strength strongly depend on <span><math><msub><mrow><mi>r</mi></mrow><mrow><mi>u</mi></mrow></msub></math></span>. Re effects in the normalized, mean velocity distributions were mainly visible in the wake associated with the finite lip thickness. In addition, increased normalized Reynolds stresses were obtained at <span><math><mrow><mi>x</mi><mo>/</mo><msub><mrow><mi>D</mi></mrow><mrow><mi>o</mi></mrow></msub><mo>≈</mo></mrow></math></span> 1.5 for the lowest Re at a given <span><math><msub><mrow><mi>r</mi></mrow><mrow><mi>u</mi></mrow></msub></math></span>. Farther downstream, Re effects became negligible as inner and outer jets merged. A comparison between different terms in the turbulent kinetic energy (TKE) budget showed that TKE is predominantly produced in the outer shear layer, while turbulent diffusion results in radial transport. Mean advection of TKE (a “sink” term) is mainly significant close to the nozzle exit.</div></div>","PeriodicalId":335,"journal":{"name":"International Journal of Heat and Fluid Flow","volume":"112 ","pages":"Article 109650"},"PeriodicalIF":2.6000,"publicationDate":"2024-12-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"International Journal of Heat and Fluid Flow","FirstCategoryId":"5","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S0142727X24003758","RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"ENGINEERING, MECHANICAL","Score":null,"Total":0}

引用次数: 0

Abstract

In this paper, planar time-resolved particle image velocimetry measurements are reported in the near-field of a coaxial jet at velocity ratios,

r_{u}

= 0.66, 1.0 and 1.32. At each

r_{u}

, at least two different Reynolds numbers, Re, were investigated. Spatial distributions of mean velocities, Reynolds stresses, vorticity and swirling strength strongly depend on

r_{u}

. Re effects in the normalized, mean velocity distributions were mainly visible in the wake associated with the finite lip thickness. In addition, increased normalized Reynolds stresses were obtained at

x / D_{o} \approx

1.5 for the lowest Re at a given

r_{u}

. Farther downstream, Re effects became negligible as inner and outer jets merged. A comparison between different terms in the turbulent kinetic energy (TKE) budget showed that TKE is predominantly produced in the outer shear layer, while turbulent diffusion results in radial transport. Mean advection of TKE (a “sink” term) is mainly significant close to the nozzle exit.

查看原文

微信好友朋友圈 QQ好友复制链接

本刊更多论文

求助全文

约1分钟内获得全文去求助

来源期刊

International Journal of Heat and Fluid Flow 工程技术-工程：机械

CiteScore

5.00

自引率

7.70%

发文量

131

审稿时长

33 days

期刊介绍： The International Journal of Heat and Fluid Flow welcomes high-quality original contributions on experimental, computational, and physical aspects of convective heat transfer and fluid dynamics relevant to engineering or the environment, including multiphase and microscale flows. Papers reporting the application of these disciplines to design and development, with emphasis on new technological fields, are also welcomed. Some of these new fields include microscale electronic and mechanical systems; medical and biological systems; and thermal and flow control in both the internal and external environment.