Session IA - Atmospheric Flows.
ORAL session, Tuesday afternoon, November 26
Ballroom E, OnCenter
Fine-scale characteristics of the atmospheric surface layer (ASL), a turbulent boundary layer with R_\theta \sim O(10^6-10^7), have been measured near the ground using multiple sensor hot-wire probes. The measurement site was in the salt flats of western Utah, where the terrain is extremely flat, uniform, and nearly devoid of growth and other flow obstructions.
For the first part of the talk, a comparison will be made between two sets of hot-wire measurements, one set from the ASL and one from a laboratory wind tunnel at R_\theta \approx 2000. The two sets have virtually identical viscous length scales and probe resolution. Each set consists of 22 simultaneous measurements at wall-normal locations of 0.4\,mm to 46\,mm, which corresponds to 2 < y^+ < 300 .
The second part of the talk will use measurements which were made in the ASL using a modular 12-sensor probe which is capable of measuring the full velocity vector and velocity gradient tensor. These measurements allow the calculation of the full dissipation rate of turbulent kinetic energy, and all scales of significant dissipation have been resolved. By conditioning upon large dissipation events, the corresponding flow physics will be examined.