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    Homogeneous, Isotropic Flow in Grid Generated Turbulence

    Source: Journal of Fluids Engineering:;2000:;volume( 122 ):;issue: 001::page 51
    Author:
    Riccardo Tresso
    ,
    Ph.D. Candidate
    ,
    David R. Munoz
    DOI: 10.1115/1.483226
    Publisher: The American Society of Mechanical Engineers (ASME)
    Abstract: Detailed grid generated turbulent analysis has been completed using a three-dimensional hot-wire anemometer and traversing mechanism to identify a homogeneous, isotropic flow region downstream of a square mesh. The three-dimensional fluctuating velocity measurements were recorded along the centerline of a wind tunnel test section and spatially over the entire wind tunnel cross section downstream of the square mesh. Turbulent intensities for various grid sizes and Reynolds numbers ranged from a minimum of 0.2 percent to a maximum of 2.2 percent in each of the three principal velocity directions. Spatial homogeneity and isotropy were determined for several turbulent flow conditions and downstream positions using the method of covariances. Covariances, in theory, should approach zero asymptotically; however, in practice, this was not achievable. A subjective judgment is required to determine downstream location where the variance of the three covariances reaches a value close to zero. The average standard deviation provides an estimate for defining the limit or subjective threshold needed to determine the onset of homogeneous, isotropic flow. Implementing this threshold, a quantitative method was developed for predicting the streamwise location for the onset of the homogeneous, isotropic flow region downstream of a 25.4 mm square grid as a function of Reynolds number. A comparison of skewness, determined from one-dimensional hot wire anemometer measurements, and covariances, determined from three dimensional hot wire anemometer measurements, indicates a need for caution when relying solely on one-dimensional measurements for determination of turbulence isotropy. The comprehensive three-dimensional characterization also provides an improved understanding of spatial distribution of fundamental turbulence quantities generated by the grid within a low-speed wind tunnel. [S0098-2202(00)02501-3]
    keyword(s): Flow (Dynamics) , Turbulence , Reynolds number , Isotropy AND Wire ,
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      Homogeneous, Isotropic Flow in Grid Generated Turbulence

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    http://yetl.yabesh.ir/yetl1/handle/yetl/123909
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    contributor authorRiccardo Tresso
    contributor authorPh.D. Candidate
    contributor authorDavid R. Munoz
    date accessioned2017-05-09T00:02:46Z
    date available2017-05-09T00:02:46Z
    date copyrightMarch, 2000
    date issued2000
    identifier issn0098-2202
    identifier otherJFEGA4-27148#51_1.pdf
    identifier urihttp://yetl.yabesh.ir/yetl/handle/yetl/123909
    description abstractDetailed grid generated turbulent analysis has been completed using a three-dimensional hot-wire anemometer and traversing mechanism to identify a homogeneous, isotropic flow region downstream of a square mesh. The three-dimensional fluctuating velocity measurements were recorded along the centerline of a wind tunnel test section and spatially over the entire wind tunnel cross section downstream of the square mesh. Turbulent intensities for various grid sizes and Reynolds numbers ranged from a minimum of 0.2 percent to a maximum of 2.2 percent in each of the three principal velocity directions. Spatial homogeneity and isotropy were determined for several turbulent flow conditions and downstream positions using the method of covariances. Covariances, in theory, should approach zero asymptotically; however, in practice, this was not achievable. A subjective judgment is required to determine downstream location where the variance of the three covariances reaches a value close to zero. The average standard deviation provides an estimate for defining the limit or subjective threshold needed to determine the onset of homogeneous, isotropic flow. Implementing this threshold, a quantitative method was developed for predicting the streamwise location for the onset of the homogeneous, isotropic flow region downstream of a 25.4 mm square grid as a function of Reynolds number. A comparison of skewness, determined from one-dimensional hot wire anemometer measurements, and covariances, determined from three dimensional hot wire anemometer measurements, indicates a need for caution when relying solely on one-dimensional measurements for determination of turbulence isotropy. The comprehensive three-dimensional characterization also provides an improved understanding of spatial distribution of fundamental turbulence quantities generated by the grid within a low-speed wind tunnel. [S0098-2202(00)02501-3]
    publisherThe American Society of Mechanical Engineers (ASME)
    titleHomogeneous, Isotropic Flow in Grid Generated Turbulence
    typeJournal Paper
    journal volume122
    journal issue1
    journal titleJournal of Fluids Engineering
    identifier doi10.1115/1.483226
    journal fristpage51
    journal lastpage56
    identifier eissn1528-901X
    keywordsFlow (Dynamics)
    keywordsTurbulence
    keywordsReynolds number
    keywordsIsotropy AND Wire
    treeJournal of Fluids Engineering:;2000:;volume( 122 ):;issue: 001
    contenttypeFulltext
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    DSpace software copyright © 2002-2015  DuraSpace
    نرم افزار کتابخانه دیجیتال "دی اسپیس" فارسی شده توسط یابش برای کتابخانه های ایرانی | تماس با یابش
    yabeshDSpacePersian