Physical simulation of resonant wave run-up on a beach

A Ezersky,N Abcha,E Pelinovsky

doi:10.5194/npg-20-35-2013

Abstract

Abstract. Nonlinear wave run-up on the beach caused by a harmonic wave maker located at some distance from the shore line is studied experimentally. It is revealed that under certain wave excitation frequencies, a significant increase in run-up amplification is observed. It is found that this amplification is due to the excitation of resonant mode in the region between the shoreline and wave maker. Frequency and magnitude of the maximum amplification are in good correlation with the numerical calculation results represented in the paper (Stefanakis et al., 2011). These effects are very important for understanding the nature of rogue waves in the coastal zone.

Highlights

Recent huge tsunamis demonstrate nonlinear behaviour on the coast leading to strong impact
It was revealed recently that the number of abnormally large and suddenly appearing waves observed in the coastal zone is sufficiently larger than Gaussian statistics predicts (Nikolkina and Didenkulova, 2011, 2012)
Analysis of tsunami records showed that reflections due to bottom topography may result in the appearance of resonant mode in the coastal zone, see for instance Neetu et al (2011)

Summary

Introduction

Recent huge tsunamis demonstrate nonlinear behaviour on the coast leading to strong impact. Stefanakis et al (2011), on the basis of numerical simulations of the nonlinear shallow-water equations, pointed out the existence of resonance effects in the process of the long wave run-up. That is why to study the run-up amplification, simultaneous measurements of the amplitude of free surface displacement near the wave maker and maximal run-up are carried out for different frequencies of excitation.

Results

Conclusion