Author(s): Jing Wang

Linked Author(s): Jing Wang

Keywords: Herschel-Bulkley constitutive relation, bilinear constitutive relation, turbidity currents, abrupt transition

Abstract: Turbidity currents are often hyperconcentrated flows of which the constitutive relations are typically non-Newtonian. Evolutions of these turbidity currents are quite distinct from those of Newtonian turbidity currents due to different viscous resistance laws. However, existing turbidity current models are mostly based on the Navier-Stokes equations, which implicitly assume the currents to be Newtonian. Here, new non-Newtonian turbidity current models are presented by first incorporating two essential non-Newtonian properties; yield stress and shear thinning, to the previous fully coupled model in the form of Herschel-Bulkley and bilinear constitutive relations, respectively. Both non-Newtonian models can be degenerated to traditional Newtonian model in dilute current cases. The models are numerically solved by Slope Limiter Centered (SLIC) scheme under the framework of finite volume method. A systematic series of lock-exchange experiments are revisited. In contrast with the limited prediction capability of traditional Newtonian model at low initial concentration of turbidity currents, the proposed models are demonstrated to perform equivalently well at low initial concentrations, in consistent with the measured data appreciably better in intermediate initial concentrations and partially reproduce the abrupt transitions at high initial concentrations. Nevertheless, the quantitative differences between numerical results and measured data necessitate further detailed investigations on the non-Newtonian properties of hyperconcentrated turbidity currents

DOI:

Year: 2017