Attenuation of waves

Abstract

Consulta en la Biblioteca ETSI Industriales (8261)

[EN] Recently, there has been a significant progress in various aspects of the wave attenuation, particularly wave breaking (Banner and Peirson (2007), Drazin et al (2008)). However, there still remain important aspects that are very poorly understood. A key problem is role of turbulence attenuation and associated of waves. This is a difficult problem not only theoretically and also experimentally. In this investigation, a laboratory study has been undertaken to quantify the role of turbulence in the attenuation of surface waves. There are many ways of generating coexisting wave and turbulent fields. In this study, we have elected to use rainfall as the source of turbulence. This was for three reasons: 1. Vertically impinging droplets can not impart horizontal momentum or energy to the wave field; 2. Rainfall is a source of near surface turbulence and therefore qualitatively similar to turbulence generated by wind or surface breaking; and, 3. The attenuation of waves by rainfall is of practical interest with regard to wave dynamics and electromagnetic interaction with open ocean surfaces. The damping of water waves by rain was mentioned by Reynolds as early as 1875. More recently the subject has been investigated by different researchers, Manton (1973), Nystuen (1989), Tsimplist (1992). In all these studies, it was assumed that the main mechanism for wave damping by rain is the result of turbulent dissipation induced by rain drops penetrating the free surface of waves. In this report, we examine quantitatively the process by which rain generated turbulence and attenuates waves. The results obtained are compared with the results with other laboratory results reported.