TURBULENT FLOWS UNDERGOING DISTORTION AND ROTATION - A REPORT ON EUROMECH-288

The 288th EUROMECH Colloquium, on the effects of distortion and rotation on turbulent motion, was held in Ecully (Ecole Centrale de Lyon) from 6-8 April 1992 with the author acting as chairman. There were fifty-five participants with widely different backgrounds. A close mutual interaction did occur between scientists interested in 'Rapid Distortion Theory' (RDT) or linear stability analysis, non-linear stability analysis, Direct (or Large Eddy) Numerical Simulation (DNS), and one- and two-point statistical approaches. Qualitative comparisons with recent experimental results were also made. Approaches in geophyiscal turbulence were compared to those used in engineering, in order to clearly display similarities and differences in conclusions despite their different terminology and 'jargon'. In addition to qualitative results on the stability and turbulence, threshold values were proposed for dimensionless numbers, close to specific Rossby numbers. Several talks illustrated how the statistical approach reflected the emergence of oriented structures. New proposals for improving one- and two-point closure models for rotational mean flows were introduced. Twenty-seven papers were presented, covering these different topics. These papers are summarized in this report with the purpose of giving an up-to-date view of current research in rotating fluids with distortion.