An experimental study of the turbulent events over a loose particle under supercritical flow conditions

Abstract

To do a complete analysis of the beginning of sediment motion the effect of turbulent fluctuations must be taken into account. In this study the quadrant method is used to analyze the different turbulent events for different established supercritical flow conditions. Detailed velocity measurements over a loose particle of a uniform spheres bed were carried out by means of a 2 component Laser Doppler Anemometer. The characterization of each event was made by means of its time duration, energy and frequency. Furthermore, the matrix associated to the event transition probability was calculated and the most probable events and transitions were determined.