Physical simulation of atmospheric flow and turbulence

A laboratory experiment on the atmospheric boundary layer (ABL) is presented. It was carried out in the large rotating tank of the Coriolis-LEGI laboratory in Grenoble. An ABL was reproduced with different roughness lengths at reduced scale and measured. In order to generate a regular mean flow, both spin up and spin down techniques were adopted by varying the rotation period of the tank. A set of preliminary measurements was performed by means of acoustic probes in order to know the velocity trend generated in the tank. The mean velocity fields and the turbulence were measured using PIV (Particle Image Velocimetry) method which allows to obtain high resolution measurements in the simulated ABL. For each rotation period two vertical (nonsimultaneous) cross sections of the flow were obtained, and 3D velocity fields reconstructed from the two planar fields under convenient geometric (orthogonal) and physical assumptions (reproducibility of the flow). Preliminary results on the analysis of the collected data are presented and discussed.