Experimental comparison between the turbidity and density currents

Understanding the mechanism of turbidity currents is important for siting submarine cables and pipelines. It is because the turbidity currents can transport a large amount of sediment in long distance that causes severe damages to these buried linear structures. It is not clear why turbidity currents can gain and sustain such a large amount of kinetic energy. One of possibilities to explain this process is a drag reduction which reduces the turbulent energy due to the inclusion of fine particles as previous studies reports. However, the influence of fine particles to their flow characteristics has not been fully elucidated. Thus, in this study, a series of model tests were conducted to compare the horizontal steady flows of silica suspension and NaCl solution in a flume. The test results show that the flow characteristics of silica suspension were different from that of NaCl solution. These differences are considered to be caused by silica particles, and it is suggested that drag reduction by fine particles would be taken place in turbidity currents.