Abstract:
In this paper, a layer-averaged fully coupled model is applied for simulating both laboratory lock-release and constant-flux turbidity currents with the aim of analyzing the applicability and uncertainties of empirical relations for the water and sediment entrainment process. For this purpose, the performance of four empirical formulae (i. e.,
ew59,
ew86,
ew87 and
ew01) for the water entrainment and five (i. e.,
Es77,
Es86,
Es87,
Es93 and
Es04) for the sediment erosion are compared. The following understandings are drawn from numerical case studies. The water entrainment has mild effect on small-scale turbidity currents, though simulation results with the
ew01 relation are slightly better than those by others. It might be due to the fact that the
ew01 relation has taken into account of the effects of both bottom and upper interface resistances. Lock-exchange turbidity currents are mainly depositional and thus less sensitive to the choice of erosion relations. For constant-flux turbidity currents, the
Es87 and
Es93 relations appear to perform best. This must be attributed to the fact only these two erosion relations have been calibrated using experimental turbidity current data. This study should help further studies for developing and calibrating empirical relations of mass exchange for turbidity currents.