Experimental Investigation of the Flow Field in the Vicinity of an Oscillating Wave Surge Converter

Moisés Brito,Rui M L Ferreira,Luis Teixeira,Maria G Neves,Luís Gil

doi:10.3390/jmse8120976

Abstract

The main objective of this paper is to characterize the flow field on the front face of an oscillating wave surge converter (OWSC) under a regular wave. For this purpose, the longitudinal and vertical velocity components were measured using an Ultrasonic Velocity Profiler (UVP). In order to explain the main trends of the OWSC’s dynamics, the experimental data were firstly compared with the analytical results of potential theory. A large discrepancy was observed between experimental and analytical results, caused by the nonlinear behavior of wave-OWSC interaction that determine the turbulent field and the boundary layer. The experimental velocity field shows a strong ascendant flow generated by the mass transfer over the flap (overtopping) and flow rotation generated by the beginning of the flap deceleration and acceleration. These features (overtopping and flow rotation) have an important role on the power capture of OWSC and, therefore, analytical results are not accurate to describe the complex hydrodynamics of OWSC.

Highlights

Oscillating wave surge converter (OWSC) devices are known to be competitive in the nearshore regions with water depth ranging between 10 to 20 m [1,2,3,4]
This paper is based on novel experimental evidence, produced under controlled conditions in a laboratory set up. It addresses the issue of characterizing the flow field in front of an oscillating wave surge converter (OWSC), highlighting the important differences between experimental and analytical results
There are several analytical models of hydrodynamic characteristics of OWSCs, this paper considers the model developed by Renzi and Dias [14]

Summary

Introduction

Oscillating wave surge converter (OWSC) devices are known to be competitive in the nearshore regions with water depth ranging between 10 to 20 m [1,2,3,4]. These devices are typically composed by a buoyant flap and by a hydraulic power take-off (PTO) system and are designed to exploit the enhanced horizontal fluid particle movement of waves in the nearshore regions [1,2,5]. In the third stage, the high-pressured fluid drives a turbomachinery which converts potential energy into electrical energy [1,2,3,4]

Objectives

Methods

Findings

Conclusion