The method of large-eddy simulation (LES) coupled with the density transport equation is employed to simulate the evolution of gravity-driven high-density turbidity current and its interaction with a pair of parallel suspended pipes. The LES method is validated first using data of a non-Boussinesq lock-exchange experiment and satisfying agreement between LES and experiment is achieved. The simulations reveal that a shear region forms between high- and low-density fluids each moving in opposite directions which leads to the generation of a series of vortices and a substantial mixing region. Close to the bottom boundary low-density fluid is entrained near the head of the high-density turbidity current, forming a thin water cushion that separates the turbidity current's head from the seabed, the so-called hydroplaning effect, thereby reducing the density of the head and bottom friction. The current study suggests that past studies which ignored density mixing may have underestimated the possibility and risk of the hydroplaning phenomena, providing new insight and evidence to support that turbidity currents have stronger disaster effects.
 

海底浊流,演化,LES