Simulations of Saline and Turbid Gravity Currents Using a Subgrid Model

This paper presents the simulations of saline and turbid gravity currents using a subgrid model, which considers the effect of density stratification on the eddy viscosity. The saline gravity current simulated here is the intrusive current in a reservoir with two layers of quiescent fluids with different densities. The suspension fluid was stored initially in a lock; instantaneous opening of the lock gate initiated the gravity current that intruded in the middle of the ambient fluid layers. The internal subgrid scale structures of the density current are observed in the simulation. The numerical model has also been applied in the simulation of turbidity current over a mildly inclined surface. The turbidity current was generated by a constant discharge of a well-sorted sediment and water mixture into the reservoir. The sediment deposition and entrainment near the bottom are considered in the simulation. The vertical velocity profile, turbidity current intrusion speed, and sediment deposition are predicted reasonably well by the numerical model.