TURBULENCE STRUCTURE OF HYDRAULIC JUMP ON HORIZONTAL BED CHANNEL

Abstract

This study concerns with the investigation of turbulence characteristics of hydraulic jump on a horizontal bed of rectangular section channel. For this purpose the experiments are performed in two phases, divided according to the supercritical flow Froude number. The first phase consisted of the study of turbulence characteristics of hydraulic jump with high Froude numbers while the second phase consisted of the study of turbulence characteristics as well as the comparison of available data with the studies from literature, on relatively lower Froude numbers. The first and second phases contain five and three experiments respectively. The turbulence characteristics of hydraulic jumps have been analyzed by using Acoustic Doppler Velocimeter (ADV). Nortek ADV and SonTek micro ADV were used for this purpose respectively. Since flow within hydraulic jump is filled with air bubbles, some errors (spikes) are contained by ADV observations in heavy turbulence, a post processing technique is therefore used to filter the recorded data. The process of filtering was also done for a single specific point. The mean velocity profiles, turbulence intensities, Reynolds stresses, normalized maximum velocities, variation of length scales, variation of maximum turbulence intensities and Reynolds stress and similarity profiles of all the hydraulic jumps have been plotted. Relationships are also proposed for some parameters of the hydraulic jump with low Froude numbers. The experimental results reveal that the turbulence characteristics of hydraulic jump with high Froude numbers are complicated and different from the hydraulic jump with low Froude numbers. The data observed for hydraulic jump with low Froude number, compared well with the studies available in literature.