An Empirical Equation for Water Entrainment of Density Current in Fixed and Converging Sections

Sedimentation is one of the most important issues of manmade reservoirs and directly case reduction in useful life of dams. Density or turbidity currents are commonly occurs in reservoir especially when the inflow associated with high sediment load. Fresh water entrainment into density currents is directly affected its transportation and other hydraulics parameters. There are some parameters that may effects water entrainment. Changing in successive cross sections is one of the parameters that may affect this parameter. In this research water entrainment of density current in converging sections is studied. Experiments were carried out in a flume with variable bed slope¡ with three convergence angle¡ three discharge¡ three concentrations and three bed slope. The results show that with increasing of converging angle water entrainment will be increase. And finally by using the data and the equations proposed by other researchers for fixed sections¡ an equation is presented for water entrainment of density current in both fixed and converging sections.