Wave attenuation and flow kinematics of an inclined thin plate acting as an alternative coastal protection structure

• The interaction of a surface piercing inclined thin plate with regular waves is experimentally tested.
• Wave attenuation, energy dissipation, and mean flow velocity profile beneath the plate is measured.
• Results reveal the dissipation mechanism of such a structure to be used in coastal protection.

This paper presents the results of a 2D experimental model application of an alternative environment-friendly coastal structure, an inclined thin plate (ITP). The primary objectives of this study were to understand (a) wave energy dissipation mechanism of ITP, (b) wave attenuation performance of ITP, and (c) the influence of ITP on water particle (orbital) velocity characteristics. In order to achieve these objectives, flume experiments were conducted for different inclination angles of ITP (i.e. 0, 5, 10, and 15°). During the experiments, water surface elevations were measured and instantaneous velocity profiles were recorded by a new generation acoustic Doppler velocimeter (ADV-Vectrino II). The experimental data revealed the fundamental physical facts regarding the dissipation mechanism and performance of ITP, which may be a base for the effective design of such coastal protection structures in the future. A tentative method based on multi-parameter regression of experimental data is proposed to determine the wave transmission performance of ITP. Finally, the practical application of an ITP structure is discussed in the light of the achieved results.