Estimation of Relative Head Velocity of Density Current When Ambient Water Flowing in Same Direction of Density Current

Density current occurs when a fluid flowing through another fluid with different density. Lot of research can be found in the literature about density current, but in all of them one of the fluids is stationary. Since no study can be found about density current when fresh water is flowing in the same direction of density current, therefore in this research attempts are made to study this especial case with the aid of experimental flume. The experiments were conducted in a flume with 35 cm wide, 8.8 m long and 70 cm height. The dense fluid was salt water with discharges of 0.5, 1 and 1.5 L/s and the discharge of fresh water were equal to 2, 3 and 4 L/s. The concentrations of dense fluid were 10, 15 and 20 g/L, and the bed slop of the flume was 0, 1 and 2%. The results showed that the head velocity is a function of the velocity of fresh water and therefore the relative head velocity is selected for further analyses. Finally, an equation is suggested to find relative head velocity.