Investigating the effect of the steep slope of the steep flow on the flow of concentrated water

In this research the effect of slope, discharge and concentration of density current on water entrainment of body and head of the flow has been studied. The effect of slope, discharge, concentration and water entrainment rate on the velocity profiles has been also studied. The experiments were carried out in a flume with solution of water, salt and pigment. The experimental model has two systems, the mixing system for making the solution and pumping system to transmit the denser liquid to flume. In total 56 experiments were performed by four discharges, seven slopes and two concentrations. The velocity profiles of body, the head’s velocity and its height were measured. The results show that by increasing discharge, slope and concentration the water entrainment in head and body increases. To estimate the water entrainment rate using Richardson Number some equations were used and finally the modified equation of Garcia (1985) was found to be the best equation among them. The head’s velocity has been also investigated by changing slope, discharge, concentration and water entrainment rate. The results show that by increasing each of them, the head’s velocity increases. The Kulgan coefficient was obtained equal to 0.64 by using the present and the other researches data. In addition a head velocity equation was derived by some dimensionless variables which they were achieved by dimensional analysis. Observations on body’s velocity profiles show that by increasing slope, discharge, concentration and water entrainment rate, the maximum velocity increases. The height of the maximum velocity also increases in high amount of discharge and water entrainment rate but it decreases for mild slopes. The results also show that the height of zero velocity zone goes up by increasing discharge, concentration and water entrainment rate but it goes down for steep slopes.