Velocity structure in interflow density currents

Document Type : Research Article


1 Department of Hydraulic structures, Shahid Chamran University,

2 department of water structurel engineering, faculty of water scienes engineering, shahid chamran university of ahvaz, ahvaz, iran


Gravity currents, also known as density currents, or turbidity currents, are happened by the density difference between the flow and its ambient fluid. The density difference can be due to suspended particles, chemicals, soluble materials, and temperature differences. In dams reservoir ambient fluid, usually has a vertical stratification. When the gravity current arrived to ambient fluid, in the position that density of both gravity current and ambient fluid is equal the gravity current abandon the bed and flows in ambient fluid horizontally. Therefore the density current into this reservoir maybe intrude such as interflow density current. This study investigates the inter flow density current in a stratification ambient. For achieve to the objectives of this study, experiments were carried out at a flumes with 9 meters long by 4 discharge 1, 1.5, 2 and 2.5 l/s, and 4 concentration 5, 10, 15 and 20 mg/l, that created density 1003.2, 1006.3, 1009.4 and 1012.5 respectively. Stratification was made by mixture water and salt with vertical gradient. The investigation of velocity profiles showed that the flow is self-similar and velocity fluctuations Continues maximum up to 2.5 times greater than current thickness in the lower layer. The front velocity of currents in stratified environments increases at first then sizeable decreases. It shows that stratified can limited the flow movement. In each three slope, increasing of discharge and concentration increase velocity head of density current in stratified environment. As the slope increases, the current velocity increases at the underflow stage, and in the interflow stage, the slope does not have much effect on the current velocity. Interflow Travel Time decrease in increasing of discharge and concentration. Density current in weaker stratified can travel more distance in the slope and separate latter from the bed.


Main Subjects

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