The Analytical Solution Of Asymmetrical Breakwater GAP Wave Diffraction

Water wave diffraction is the phenomenon where waves encounter an obstacle or gap and propagate into a sheltered area at a different angle than the original wave train.By understanding the physical process of wave diffraction,a designer can properly prevent diffracted wave energy from causing significant agitation within the shadow zone.In the present paper,the analytical solutions are derived for diffraction of normal incident water waves by the gap between two rigid and long breakwaters with a relatively arbitrary configuration.The analytical solution of asymmetrical breakwaters was obtained by superimposing the solution of left single breakwater and right single breakwater,and then taking some necessary manipulations to comply with the physical phenomenon.The analytic solution has been derived for the diffraction of water waves around a semiinfinitely long and rigid breakwater by Penney and Price.The correctness of the solutions for asymmetrical breakwater gap have been verified by compare with the results of experiments and numerical solution.Moreover,the solutions were also compared with a numerical solution based on the Berkhoff equation which solved by finite element method.For the verification of the solution for parallel asymmetry breakwater gap,the diffraction coefficient distribution were compared with Pos' s experiment.Similarly,the solution for the asymmetrical breakwater with certain angles was verified by Memos' s experimental results and numerical solution.The agreement is excellent.For the parallel asymmetry breakwater gap,the diffraction coefficient distribution is asymmetrical.Behind the relatively backward lead breakwater,the attenuation is relatively slow.There is an amplification of diffraction coefficient behind the harbor entrance,and it will be harmful for the navigation near the entrance.For the asymmetrical breakwater with certain angles,the diffraction coefficient will increase behind the rotated breakwater.The diffraction of infragravity waves around asymmetry breakwater gap was researched by analytical solution and mild slope equation model.When the ratio of gap width to the wave length less than 2,the deviation of analytical solution is great.Meanwhile,the effect of breakwater will decrease when the length of incident waves are great.