Numerical simulation on flow characteristics of large-scale submarine mudflow

Abstract

Gas hydrate (GH) is widely distributed in the world according to the geological survey. Most of GH is located in the ocean. After GH dissociation, the strength of gas hydrate bearing sediments (GHBS) decreases accompanying the rise of pore pressure, which can cause marine landslide. Landslide may transform into mudflows during movement on the seabed. The massive movement of submarine mudflow can result in the serious deformation of (or even damage of) submarine pipelines, the dumping of offshore platforms, and tsunamis. In this paper, the flow characteristics of the large-scale submarine mudflow are investigated based on the Euler-Euler multiphase flow model combining with kinetic theory of granular flow (KTGF). The controlling dimensionless parameters, such as the initial depositional form and the relative depth, are given. The hydroplaning and frontal detachment during the mass movement are captured. The front velocity of the mudflow, and the free surface elevations at the sea level are analyzed. The numerical results show that the large-scale submarine mudflow has a significant impact on the sea level. The submarine mudflow should be taken into consideration during design of submarine pipelines and offshore platforms in GH-distributed sea area duo to its great destructive power.