CHARACTERIZING TRAILING WAVES FROM CARGO SHIP WAKE

Abstract

Low-frequency (LF) cargo ship wake is a major source of hydrodynamic energy in shipping channels, where it has increasingly been linked to shoreline erosion. The LF wake consists of a drawdown called the “Bernoulli depression,” a return surge, and finally a series of trailing waves that may persist longer than 30 minutes after the vessel passage. While the Bernoulli depression and surge are well-explained by conservation principles, we presently lack a robust explanation of the trailing waves. They are a ubiquitous feature observed at many locations (e.g. Garrel, Lopez, and Collins, 2008), and have frequently been attributed to cross-channel seiching; however, field measurements from the Savannah River, GA, USA suggested that some of the waves may have alongshore progressive characteristics, which contradicts this assumption.