ABSTRACT

Wave-body interaction problems are of great interest to engineers ensuing from the industrial and environmental significance. A two-dimensional numerical wave flume is constructed based on Constrained Interpolation Profile (CIP) method, to investigate the interaction between a solitary wave and a trapezoid obstacle on the sloping beach. First, convergence tests are presented with respect to time step and mesh resolution. Second, the free surface elevation measured by wave gauges at different locations is presented to analyze the variation of solitary wave on this slope. Then, the evolution process of solitary waves on the slope is presented. Finally, the weather side dynamic force on the trapezoid obstacle is obtained by integrating the forces acting on each virtual particle.

INTRODUCTION

Types of seawalls have been constructed for shore protection and harbor shelter. Vertical seawall can cause significant wave reflection and large scour at the toe of the structure. Submerged breakwaters allow water circulation and cost less than vertical seawalls, but have a lower protection than vertical seawalls and are affected by the navigation hazards (Brossard, 2003). Breakwaters near the free surface are applied to dissipate the maximum energy flux. Sloped seawalls are considered to be better energy dissipaters, compared with vertical seawall, attributing to the mild slope (Neelamani and Sandhya, 2003). Hsiao and Lin (2010) proposed a trapezoid seawall on a 1:20 slope which is employed in this paper. Liu and Banaa (2004), Wu and Hsiao (2013) investigated solitary waves interacted with vertical obstacles through experiments. Numerical studies mostly focus on vertical seawall such as Liu and Abbaspour (1982), Losada et al (1994), and both of them employed short waves, while little attention has been devoted to long waves such as solitary waves.

As a fair representation of nonlinear shallow water waves, solitary waves are used in some analytical studies because it is completely characterized by nonlinearity, so that the number of influential parameters are reduced into one (Lin, 2004). Solitary waves also can be applied as a model of a tsunami. When the incident wave height increases, wave breaking might occur and the analytical results become invalid. The solution of this kind of problem can partially rely on the computational fluid dynamics.

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