Experimental Investigation of 3-D Turbulent Currents

In this investigation, the effect of different parameters on the behavior of three-dimensional, turbulent, and steady state turbidity currents has been studied experimentally. One of the important parameters which show the hydrodynamics of turbidity current is the velocity profiles and in this investigation, it has been measured by ADV (Acoustic Doppler Velocimetery). Kaolin with specific gravity of 2.65 was used as suspended material. The mean particle diameter (D50) is approximately 11 micron. The results show that by increasing the entrance volume flux of turbidity current the height of turbidity current increase. An increase in entrance concentration and slope often would decrease the height of turbidity current. In addition, due to the intense entrainment in the lateral and longitudinal directions, along the interface of fresh water and turbidity current, the height of the current is increased after entering this channel. The velocity profiles show that a high inertia force exists at the entrance region near the source where the maximum and average velocity is high. Towards the end of the tank; it is observed that the location of maximum velocity is shifted upward. After entering the channel, turbidity current moves forward down-slope, spreads laterally and shows behavior of developed flow which entrainment rate remains constant. Experiments also show that this density current preserve its three dimensional structure after reaching the side walls.