Numerical Simulations of Wave Diffraction Around a Low-Crested Semicircular Breakwater

Wave diffraction is a phenomenon of lateral energy transferring along the wave crest. This phenomenon could be seen as the waves being disrupted by a barrier (breakwater). In past decades, semi-circular breakwater (SCB) has been used to protect the coastal areas and has a semi-circular shaped hollow caisson founded on top of a rubble mound. Analysis method utilizing 1-Dimensional (1D) study is common in past research, yet the method dampened to provide vital phenomenon data likewise the diffracted wave height. 2-Dimensional (2D) study approach is viable to provide such data. Thus, it was employed for this study. Besides, previous research only focused on large-scale structures, and this study will focus on a small-scale structure since muddy coast is available in Malaysia. Hence, this paper aims to evaluate wave diffraction within submerged and emerged SCB vicinity subjected to regular waves using numerical modelling (FLOW 3D). Flow 3D is capable of handling coastal issues, especially for evaluating 3-Dimensional (3D) problems, i.e., wave diffraction. This paper focused on regular waves using wave period, 0.8 s, water depth, 0.4 m and wave steepness, 0.02. As a result, the wave diffraction coefficient, Kd value, showed a decreasing trend as the relative breakwater width, B/L value, increased. © 2023, The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd.