Stability criterion for the surface of the deposit bed of solid-liquid flows in horizontal pipes

During the transport of coarse particles through a pipeline, if unexpected accidents such as sudden pump stoppage due to failure of the power supply occurs, particles in the pipeline settle and form a deposit bed in the pipe bottom. In such cases, the settled particles must be removed prior to resuming operation. There are several ways of removing particles deposited in pipelines. One of them uses fluid drag force. In this paper we propose a new criterion: the fluid velocity at which dunes are formed on the surface of the deposit bed, taking into account both the shortening of removal time and the avoidance of pipe blockage. The stability criterion for the surface of the deposit bed in pipelines was theoretically and experimentally studied by using the linear stability theory.