Author(s): Zhimeng Zhang; Chunning Ji; Yee-Meng Chiew

Linked Author(s): Yee Meng Chiew

Keywords: Submarine pipelines; Local scour; Vibrating pipeline; Equilibrium scour depth; Time scale

Abstract: Submarine pipelines are widely used to transport gas and oil from production wells to processing facilities in offshore engineering. Pipelines that oscillate above the seabed intensify local fluid motions and augment the sediment transport, thereby exacerbating the formation of scour holes beneath the pipelines, which can impact the design of near-seabed infrastructures in the offshore industry. The equilibrium scour depth and time scale of the scour process are the two main factors required to describe the scour development, which is essential in the design of offshore pipelines. The equilibrium scour depth around a fixed pipeline has been studied extensively in two- and three-dimensional model experiments and numerical models in steady currents (Chiew 1991; Liang et al., 2005; Fuhrman et al., 2014), in waves (Sumer and Fredsoe, 1990), and combined waves and currents (Zhang et al., 2016). To describe the temporal development of the local scour depth under clear-water conditions, an exponential function was proposed by Cheng et al. (2016) as follows: ds(t)/dse = 1 - exp[-Ce(t/Te)ne] (1) where ds(t) = maximum scour depth at time t, dse = equilibrium scour depth, Te = time scale for the equilibrium state, Ce = coefficient, and ne = exponent.

DOI:

Year: 2023