线性长波越过水下环礁引起的Bragg共振分析  

Study on Bragg Resonance Caused by Linear Long Wave Crossing Submerge Atoll

作　　者：傅丹娟 刘必劲 毛豪东 张振伟 FU Danjuan;LIU Bijin;MAO Haodong;ZHANG Zhengwei(School of Civil Engineering and Architecture,Xiamen University of Technology,Xiamen 361024,China;Hainan Institute,Zhejiang University,Hainan 572025,China)

机构地区：[1]厦门理工学院土木工程与建筑学院,福建厦门361024 [2]浙江大学海南研究院,海南三亚572025

出　　处：《厦门理工学院学报》2023年第5期75-81,共7页Journal of Xiamen University of Technology

基　　金：福建省自然科学基金项目(2022J05282);海南省自然科学基金项目(422MS090)。

摘　　要：采用线性长波方程对水下环礁波浪的传播变形进行解析模拟,并建立散射系数的解析公式,根据散射系数,分析环礁地形上Bragg共振的存在性与存在条件。结果表明:当环礁中心泻湖深度足够深时,会激发其迎浪正面的Bragg共振,即在2S/L=1附近产生主共振,在的2S/L=2、2S/L=3附近,散射系数取得极大值,但是共振规律随着方位的偏移及泻湖深度的变浅而逐渐消失。另外还发现,在一些特定的入射波频率下,环礁可激发其他方位上的共振,如在2S/L=2.24频率下,迎浪面θ=3π/4方位上的散射强,而正面θ=π散射小。The propagation and deformation of waves with atoll is analyzed using the linear long-wave equation,the analytical formula of scattering coefficient is established and the existence of Bragg resonance on the atoll analyzed according to the scattering coefficient.The results show that the Bragg resonance on the front side of the wave will be excited with sufficient depth of the lagoon in the center of the atoll,or the main resonance generated around 2S/L=1,and the scattering coefficient will reach a maximum value near 2S/L=2,2S/L=3,but the resonance pattern will gradually disappear with deviating of the orientation and shallowing of the lagoon.Also,the atoll can excite resonance in other directions at some specific incident wave frequencies such as 2S/L=2.24,where the scattering is strong in the orientation ofθ=3π/4 and small in the front of θ=π.

关 键 词：Bragg共振 线性长波 环礁 散射系数 解析分析 

分 类 号：TV148[水利工程—水力学及河流动力学]