An Analysis of changes in hydraulic parameters on water entrainment in converging channels

Building of Dam from thousands of years BC was known, and the humans with use of them alwaystry to preserve and utilize surface water resources, but sedimentation problem always is the mostimportant factor in shortening the useful life of dams , and a lot of reservoirs were filled by sedimentsdue to this process and therefore most of dams have been abandoned. One of the most importantphenomena that affects sedimentation is density current. Research must be continue to recognize therole of this phenomena in sediment process. In this research the effect of changes in parameters suchdischarges, concentration and slope gradient in density currents were investigated in the convergingchannels. Experiments were carried out in a flume with changeable bed slope, width 72.5 cm, depth 60cm, Length 6 meter, three convergence angle, three discharge, three concentrations and three bed slopein laboratory models of hydraulic of Shahid Chamran University. The results showed that increase ofdischarges and slope gradient will increase water entrainment and increasing of concentration willdecrease it. Finally an equation is presented for water entrainment in each convergent angle.