Yamazaki, H. Tokyo University of Fisheries, hide@tokyo-u-fish.ac.jp
Squires, K. Arizona State University, squires@asu.edu

Making use of observed oceanic turbulence, the dynamic range of turbulence in the upper ocean is reviewed. The published turbulence data are, in general, a locally averaged dissipation rate of the kinetic energy. The averaging scale is on the order of one meter. Therefore, the average does not represent the immediate flow field of a micro-organism, whose length scale is on the order of a millimeter. Yamazaki and Lueck (1990) reported that the locally averaged dissipation rate whose length scale is as small as three times the Kolomogorov scale distributed lognormally. We have investigated if the lognormal theory is applicable to a moderate range of Reynolds number flows using Direct Numerical Simulation. We have found the lognormal theory can accurately describe locally averaged dissipation rates for such moderate Reynolds number as well. Hence, the lognormal theory is a powerful tool to investigate how the local structure of the flow field may appear to micro-organisms. We will quantify shear fields at a comparable scale with micro-organisms making use of the lognormal theory.
Day: Tuesday, Feb. 2
Time: 08:30 - 08:45am
Location: Hilton of Santa Fe
Code: SS02TU0830H