BANG1D: a one-dimensional, Lagrangian model of subaqueous turbid surges

BANG1D simulates the mechanics of a subaqueous, turbid surge, a seafloor-fa ilure-induced turbidity current that behaves like a snow avalanche or a pyr oclastic burst. BANG1D uses the one-dimensional, layer-averaged equations f or the conservation of fluid, sediment, momentum and turbulent kinetic ener gy in a turbidity current. The Lagrangian forms of these equations are solv ed explicitly at nodes within the turbid surge as they are tracked moving a t discrete time steps across a bathymetric profile. BANG1D simulations comp are well with experimental data of turbid Rows and with simulations produce d by other numerical models. Intermodel comparisons demonstrate the importa nce of frictional drag at the base of a turbid Row and entrainment across i ts surface in retarding accelerations induced by fluid pressures and gravit y. Sensitivity tests also show that a constraint must be placed on the eros ive power of the how, This is accomplished in BANG1D by coupling the shear velocity at the base of the flow to its turbulent kinetic energy. Use of th is coupling results in successful simulations of experimental sediment-lade n turbid Rows, but not experimental saline Rows, which do not carry sedimen t. This latter finding suggests that additional research is needed into the linkage between frictional drag along a sedimentary boundary and the turbu lent kinetic energy in turbid flows. (C) 2001 Elsevier Science Ltd. All rig hts reserved.