SWASH ZONE BASED REFLECTION DURING ENERGETIC WAVE CONDITIONS AT A DISSIPATIVE BEACH: TOWARD A WAVE-BY-WAVE APPROACH

Proceedings of the International Conference on Coastal Engineering

Juan Carlos Aguilera¹  Raimundo Ibaceta¹  Rodrigo Cienfuegos¹  Bruno Castelle¹  Mauricio Villagran¹  Christopher Blenkinsopp¹  Patricio Catalan¹  Rafael Almar¹ 

关键词: Mataquito;    Maule Region;    Chile;    beach reflection;    incoming and outgoing wave separation;    swash measurements technique;    video;    Lidar;   

DOI  :  10.9753/icce.v34.currents.34

学科分类：建筑学

来源: Coastal Engineering Research Council

【 摘 要 】

This paper presents a 11-day experiment conducted at the high-energy dissipative beach of Mataquito, Maule Region, Chile. During the experiment, offshore significant wave height ranged 1-4 m, with persistent long period up to 18 s and oblique incidence. Wave energy reflection value ranged from 1 to 4 %, and results show that it is highly linked to both incoming wave characteristics and swash zone beach slope, and is well correlated to a swash-slope based Iribarren number. The swash acting as a low-pass filter in the reflection mechanism, our results show that the cut-off period is better determined by swash slope rather than incoming wave's period. A new low cost technique for observing high-frequency swash hydro-morphodynamics is introduced and validated using LIDAR measurements. A good agreement is found. Separation of uprush and backswash components using the Radon Transform illustrates the low-frequency filtering effect. These results show the key role played by swash mechanism in the reflection rate and frequency selection. More investigation is needed to describe the reflection process and its link with shoreface evolution, moving toward a swash-by-swash approach.

【 授权许可】

Unknown