{"title":"Cylinder wake flow in confined channel and its active control by sweeping jets","authors":"Jinsheng Song, Zihao Qiu, Yingzheng Liu, Xin Wen","doi":"10.1007/s00348-024-03910-0","DOIUrl":null,"url":null,"abstract":"<div><p>The wake dynamics of the flow past a confined circular cylinder and its active control by sweeping jets (SWJs) and steady jets (SJs) positioned at the front stagnation points were experimentally investigated using particle image velocimetry and pressure measurements. Experiments were conducted across a range of Reynolds numbers (Re, based on the incoming flow velocity and the cylinder diameter) from 10,000 to 45,000 and blockage ratios (<span>\\(\\beta\\)</span>) of <span>\\(1/2\\)</span>, <span>\\(1/3\\)</span>, <span>\\(1/4\\)</span>, and <span>\\(1/5\\)</span>. A comprehensive comparison between the current results and existing literature on natural flow dynamics fills the knowledge gap and reveals that confinement gradually reduces the time-average pressure coefficient (<span>\\(C_{{\\text{p}}}\\)</span>) and increases the drag coefficient (<span>\\(C_{{\\text{D}}}\\)</span>) and Strouhal number (St). The interaction between the wake and lateral wall shear layer gradually increased as <span>\\(\\beta\\)</span> increased. Both SWJs and SJs effectively suppressed wake fluctuations, and the statistical characteristics of the flow field and proper orthogonal decomposition analysis indicated a consistent flow control mechanism between the two methods. However, the SJs introduced external fluctuations and unbalanced forces in the forward flow field, resulting in a wake flow asymmetry. By contrast, SWJs provide more uniform control and superior flow control effectiveness and efficiency.</p></div>","PeriodicalId":554,"journal":{"name":"Experiments in Fluids","volume":null,"pages":null},"PeriodicalIF":2.3000,"publicationDate":"2024-11-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Experiments in Fluids","FirstCategoryId":"5","ListUrlMain":"https://link.springer.com/article/10.1007/s00348-024-03910-0","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
The wake dynamics of the flow past a confined circular cylinder and its active control by sweeping jets (SWJs) and steady jets (SJs) positioned at the front stagnation points were experimentally investigated using particle image velocimetry and pressure measurements. Experiments were conducted across a range of Reynolds numbers (Re, based on the incoming flow velocity and the cylinder diameter) from 10,000 to 45,000 and blockage ratios (\(\beta\)) of \(1/2\), \(1/3\), \(1/4\), and \(1/5\). A comprehensive comparison between the current results and existing literature on natural flow dynamics fills the knowledge gap and reveals that confinement gradually reduces the time-average pressure coefficient (\(C_{{\text{p}}}\)) and increases the drag coefficient (\(C_{{\text{D}}}\)) and Strouhal number (St). The interaction between the wake and lateral wall shear layer gradually increased as \(\beta\) increased. Both SWJs and SJs effectively suppressed wake fluctuations, and the statistical characteristics of the flow field and proper orthogonal decomposition analysis indicated a consistent flow control mechanism between the two methods. However, the SJs introduced external fluctuations and unbalanced forces in the forward flow field, resulting in a wake flow asymmetry. By contrast, SWJs provide more uniform control and superior flow control effectiveness and efficiency.
期刊介绍:
Experiments in Fluids examines the advancement, extension, and improvement of new techniques of flow measurement. The journal also publishes contributions that employ existing experimental techniques to gain an understanding of the underlying flow physics in the areas of turbulence, aerodynamics, hydrodynamics, convective heat transfer, combustion, turbomachinery, multi-phase flows, and chemical, biological and geological flows. In addition, readers will find papers that report on investigations combining experimental and analytical/numerical approaches.