On the effects of wave drift on the dispersion of floating pollutants

• Published in: Ocean engineering Vol. 28; no. 10; pp. 1339 - 1348
• Main Authors: Giarrusso, C.C., Pugliese Carratelli, E., Spulsi, G.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier Ltd 01.10.2001; Elsevier
• Subjects: Applied sciences; Earth, ocean, space; Exact sciences and technology; External geophysics; Floating pollutants; Marine; Natural water pollution; Oil Slick; Physics of the oceans; Pollution; Random dispersion; Random drift; Random field simulation; Sea surface; Sea surface pollution; Seawaters, estuaries; Thermohaline structure and circulation. Turbulence and diffusion; Water treatment and pollution; Wave drift; Wave random field; Oil Slick; Wave random field; Sea surface; Random field simulation; Sea surface pollution; Floating pollutants; Wave drift; Random drift; Random dispersion; Random field; Wave effect; Numerical simulation; Hydrodynamic dispersion; Drift; Water pollution; Ocean dynamics; Trajectory; Float power
• ISSN: 0029-8018
• DOI: 10.1016/S0029-8018(00)00072-X

The movement of floating pollutants such as oil slicks on the surface of the sea is due to a number different factors, among which wave drift is certainly significant. In principle, it has been known since Stokes' time that a floating particle is subject to the movement caused by the orbital motion of water particles and that an average drift velocity results because the trajectories are not closed. In the past, however, this effect was often either disregarded or simply included with the surface wind induced current. In recent times the difference between the two effects has been conceptually clarified, so that the average wave drift in random one-dimensional seas has been the object of research and the results are now included in most handbooks and models for oil slick forecasting. Due to the chaotic nature of the wave field, however, the drift also causes floating substances to disperse, and this phenomenon is a much more neglected area of research. Recent work by Bovolin et al. [IAHR Congress, 1997] and Sobey and Barker [J. Coast. Res. 13 (1997)] has brought the subject to attention, and computational tools can now be made to quantify the effect and to verify when and how it should be taken into consideration in oil slick accident practise. The work presented in this paper is based on random simulation of the wave induced Eulerian velocity field in a directional sea, by making use of standard offshore wave directional models and on the ensemble averaging of floating particles trajectories in order to compute the spatial dispersion.