Simulation of Scour around a Vibrating Pipe in Steady Currents

Abstract

A vertical two-dimensional numerical model is employed to study the scour beneath a vibrating pipe exposed to steady currents. The ability of the model is first validated against previous scour experiments concerning both fixed and vibrating pipes. Both the development of scour depth and the final bed profile are generally well reproduced by the model. Subsequently, a broad range of the vibration parameters, including the amplitude and frequency, are tested to reveal their influences on the equilibrium scour depth. A generic relationship between the vibration frequency, amplitude, and scour depth is established by constructing suitable nondimensional groups. The maximum scour depth is shown to increase with the vibration amplitude and frequency. At small frequencies, both the frequency and amplitude have a pronounced influence on the scour depth; with the increase of the vibration frequency, the influence of the frequency gradually diminishes and the scour depth is mainly decided by the vibration amplitude. Two empirical formulas are proposed to describe the quantitative relationship between the frequency, amplitude, and scour depth.