University of Tabriz Water and Soil Science 2008-5133 28 3 2018 09 23 Experimental Investigation and Assessment of Turbidity Current Head Dynamic Over a Mobile Bed Experimental Investigation and Assessment of Turbidity Current Head Dynamic Over a Mobile Bed 131 140 8142 FA A Sharifnezhad Ph.D. student, Dept. of Water Struc., Faculty of Water Sciences Engin., Univ. of Shahid Chamran of Ahvaz, Iran SM Kashefipour Prof., Dept. of Water Struc., Faculty of Water Sciences Engin., Univ. of Shahid Chamran of Ahvaz, Iran M Ghomshi Prof., Dept. of Water Struc., Faculty of Water Sciences Engin., Univ. of Shahid Chamran of Ahvaz, Iran Journal Article 2018 11 20 Turbidity current phenomenon is one of the most important factors in reservoir sedimentation and sediment distribution, which causes management and operational problems and decreases dam’s useful life. Study and investigation of progressive section (head of turbidity current), as the most significant and considerable section is essential for sustainable management of dam reservoirs. So far, most of the studies have been conducted under experimental conditions on rigid beds. But In this study, in order to achieve more realistic results regarding natural conditions in rivers and reservoirs, the experiments were carried out on an erodible and mobile bed. So dynamic of turbidity current head was analyzed on rigid and erodible beds for different effective hydraulic conditions. It was shown that erodible bed increased the head velocity of turbidity current and Keulegan coefficient up to about 20% and also, increased the relative forehead height up to about 40% with increasing flume bed slope. In addition, in order to estimate the averaged head velocity, an equation with correlation coefficient of 0.86, was developed using multivariate linear regression and effective dimensionless parameters. Finally sensitivity analysis of the equation’s dimensionless parameters showed that the most effective parameter in estimation of the head velocity average is Richardson number. Turbidity current phenomenon is one of the most important factors in reservoir sedimentation and sediment distribution, which causes management and operational problems and decreases dam’s useful life. Study and investigation of progressive section (head of turbidity current), as the most significant and considerable section is essential for sustainable management of dam reservoirs. So far, most of the studies have been conducted under experimental conditions on rigid beds. But In this study, in order to achieve more realistic results regarding natural conditions in rivers and reservoirs, the experiments were carried out on an erodible and mobile bed. So dynamic of turbidity current head was analyzed on rigid and erodible beds for different effective hydraulic conditions. It was shown that erodible bed increased the head velocity of turbidity current and Keulegan coefficient up to about 20% and also, increased the relative forehead height up to about 40% with increasing flume bed slope. In addition, in order to estimate the averaged head velocity, an equation with correlation coefficient of 0.86, was developed using multivariate linear regression and effective dimensionless parameters. Finally sensitivity analysis of the equation’s dimensionless parameters showed that the most effective parameter in estimation of the head velocity average is Richardson number. https://water-soil.tabrizu.ac.ir/article_8142_c77616cf6372dec6f2a77b63cb940cf5.pdf