ABSTRACT
ABSTRACT: Experimental flows of turbidity currents are investigated using photometric analysis. The present work studies the interaction of turbidity currents with different obstacles and substrates, using a 25 mm square-bottomed cylinder obstacle, and a 0.8 mm rough surface for the entire base of the test basin. Notable differences are evident in the nature and characteristics of current flows. The rough substrate decreases current velocity and minimises the appearance of turbidity current phenomena, such as lobe and cleft formation and Kelvin-Helmholtz billows. Presence of an obstacle causes localised decreases in velocity, but otherwise has little effect on overall velocity of the flow. Lobe and cleft formations increase significantly after the current passes over an obstacle. It is concluded that these findings warrant the inclusion of rough substrates in further experimental testing. A generally used smooth laboratory substrate does not take into account substrates encountered in nature, and our preliminary study shows that there are significant flow characteristic differences. The presented work is based on limited tests, it is recommended to undertake a more comprehensive study to evaluate the substrate roughness effect.
