Author(s): A. Zeris; P. Prinos
Linked Author(s): Panagiotis Prinos
Keywords: Coherent Structures; Quadrant Splitting; VITA; Turbulent Flow; Bed Suction
Abstract: In this study Quadrant Splitting (QS) and Variable Interval Time Average (VITA) techniques are applied for analyzing and quantifying the appearance of events related with coherent structures. Experimental velocity signals in turbulent, fully developed, open channel flow, without and with the impose of bed suction are analyzed using Laser Doppler and HotFilm techniques. The effect of the threshold level H on the fractional contribution from each quadrant is investigated with the QS method and the contribution of ejections and sweeps to the Reynolds stress is extracted for regions inside the suction zone and after the suction strip. With the VITA method the dependence of intense events on time window and threshold value is examined and events, inside and at the exit of the suction region, are extracted for signals obtained with Hot-Film and Laser Doppler anemometry.
Year: 2003