Instantaneous measurement of velocity fields in developed thermal turbulence in mercury
Abstract
Using ultrasonic velocimetry we measured the vertical profile of the velocity fluctuation in highRayleighnumber thermal convection in a cell with aspect ratio of 0.5, filled with a lowPrandtlnumber fluid, mercury. The intriguing fluctuating dynamics of the mean flow and universal nature of the kinetic energy cascade are elucidated utilizing spectral decomposition and reconstruction. The scaling properties of the structure functions and the energy spectrum are directly calculated without the use of Taylor’s frozenflow hypothesis. Despite the complex nature of the mean flow, it is found that the energy cascade process exhibits universal laws in thermal turbulence.
 Publication:

Physical Review E
 Pub Date:
 March 2004
 DOI:
 10.1103/PhysRevE.69.036306
 arXiv:
 arXiv:condmat/0310445
 Bibcode:
 2004PhRvE..69c6306M
 Keywords:

 47.27.Jv;
 05.40.a;
 HighReynoldsnumber turbulence;
 Fluctuation phenomena random processes noise and Brownian motion;
 Condensed Matter  Disordered Systems and Neural Networks
 EPrint:
 4 pages, 5 figures