Wave reflection from vertical breakwater with porous structure

This paper presents numerical solutions for the wave reflection from submerged porous structures in front of the impermeable vertical breakwater. A new time-dependent mild-slope equation involves the parameters of the porous medium including the porosity, the friction factor and the inertia coefficient, etc. is derived for solving the boundary value problem. A comprehensive comparison between the present model and the existing analytical solution for the case of simple rectangular geometries of the submerged structure is performed first. Then, more complicated cases such as the inclined and trapezoidal submerged porous structures in front of the vertical breakwater with sloping bottom are considered. This study also examines the effects of the permeable properties and the geometric configurations of the porous structure to the wave reflection. It is found that the submerged porous structure with trapezoidal shape has more efficiency to reduce the wave reflection than that of triangular shape. The numerical results show that the minimum wave reflection is occurred when the breakwater is located at the intermediate water depth.

[1]  G. Copeland,et al.  A practical alternative to the “mild-slope” wave equation , 1985 .

[2]  Akira Watanabe,et al.  Numerical Modeling of Nearshore Wave Field Under Combined Refraction, Diffraction and Breaking , 1986 .

[3]  Chung-pan Lee,et al.  Wave interaction with permeable structures , 1987 .

[4]  Inigo J. Losada,et al.  3-D non-breaking regular wave interaction with submerged breakwaters , 1996 .

[5]  Dong-Soo Hur,et al.  Numerical estimation of the wave forces acting on a three-dimensional body on submerged breakwater , 2003 .

[6]  Ralph H. Cross,et al.  WAVE TRANSMISSION THROUGH PERMEABLE BREAKWATERS , 1972 .

[7]  M.R.A. van Gent,et al.  Wave Action On and In Permeable Structures , 1995 .

[8]  Akira Watanabe,et al.  A Mathematical Model of Wave Transformation over a Submerged Breakwater , 1989 .

[9]  Wojciech Sulisz,et al.  Wave reflection and transmission at permeable breakwaters of arbitrary cross-section , 1985 .

[10]  Kuang-An Chang,et al.  Numerical Modeling of Wave Interaction with Porous Structures , 2001 .

[11]  Robert A. Dalrymple,et al.  Reflection and transmission from porous structures under oblique wave attack , 1991, Journal of Fluid Mechanics.

[12]  Ole Secher Madsen,et al.  Wave Transmission through Porous Structures , 1974 .

[13]  Tsutomu Sakakiyama,et al.  A numerical model for wave motions and turbulence flows in front of a composite breakwater , 2002 .

[14]  P. Troch,et al.  Development of two-dimensional numerical wave flume for wave interaction with rubble mound breakwaters , 1999 .