{
  "id": "1012.0153",
  "version": "v2",
  "published": "2010-12-01T10:58:02.000Z",
  "updated": "2011-01-19T10:31:14.000Z",
  "title": "Experimental Investigation of Longitudinal Space-Time Correlations of the Velocity Field in Turbulent Rayleigh-Bénard Convection",
  "authors": [
    "Quan Zhou",
    "Chun-Mei Li",
    "Zhi-Ming Lu",
    "Yu-Lu Liu"
  ],
  "comment": "16 pages, 15 figures, submitted to J. Fluid Mech",
  "categories": [
    "physics.flu-dyn"
  ],
  "abstract": "We report an experimental investigation of the longitudinal space-time cross-correlation function of the velocity field, $C(r,\\tau)$, in a cylindrical turbulent Rayleigh-B\\'{e}nard convection cell using the particle image velocimetry (PIV) technique. We show that while the Taylor's frozen-flow hypothesis does not hold in turbulent thermal convection, the recent elliptic model advanced for turbulent shear flows [He & Zhang, \\emph{Phys. Rev. E} \\textbf{73}, 055303(R) (2006)] is valid for the present velocity field for all over the cell, i.e., the isocorrelation contours of the measured $C(r,\\tau)$ have a shape of elliptical curves and hence $C(r,\\tau)$ can be related to $C(r_E,0)$ via $r_E^2=(r-\\beta\\tau)^2+\\gamma^2\\tau^2$ with $\\beta$ and $\\gamma$ being two characteristic velocities. We further show that the fitted $\\beta$ is proportional to the mean velocity of the flow, but the values of $\\gamma$ are larger than the theoretical predictions. Specifically, we focus on two representative regions in the cell: the region near the cell sidewall and the cell's central region. It is found that $\\beta$ and $\\gamma$ are approximately the same near the sidewall, while $\\beta\\simeq0$ at cell center.",
  "revisions": [
    {
      "version": "v2",
      "updated": "2011-01-19T10:31:14.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "velocity field",
      "longitudinal space-time correlations",
      "turbulent rayleigh-bénard convection",
      "experimental investigation",
      "longitudinal space-time cross-correlation function"
    ],
    "tags": [
      "journal article"
    ],
    "publication": {
      "doi": "10.1017/jfm.2011.249",
      "journal": "Journal of Fluid Mechanics",
      "year": 2011,
      "month": "Sep",
      "volume": 683,
      "pages": 94
    },
    "note": {
      "typesetting": "TeX",
      "pages": 16,
      "language": "en",
      "license": "arXiv",
      "status": "editable",
      "adsabs": "2011JFM...683...94Z"
    }
  }
}