Author(s): Richard I Wilson; Heide Friedrich; Craig Stevens

Linked Author(s): Richard Wilson, Heide Friedrich

Keywords: Instability; obstacle; sediment-laden flow; unconfined; visualization

Abstract: Experimental studies of confined turbidity currents interacting with obstacles have become popular over the last three decades; however, little work has sought to quantify the characteristics of unconfined turbidity currents interacting with obstacles. In the present study, unconfined turbidity currents colliding with a rectangular basal obstruction are investigated. With a focus on the initial theoretical slumping regime, flow characteristics are quantified and characterized. The currents varied with initial density and substrate roughness. Unobstructed currents propagated at a constant velocity, confirming previous theory that the current is within the slumping regime; however, a typical reverse ambient bore was not present. Froude and Reynolds numbers were shown to decrease over the obstacle by 43–54% and 17%, respectively. Deflected lateral propagation along the obstacle face was found to entrap ambient fluid and encourage mixing, providing a starting point for understanding the implications of lateral propagation along submerged pipelines and reservoir barriers.

DOI: https://doi.org/10.1080/00221686.2018.1494054

Year: 2019