摘要
为研究人工岛沿波浪传播方向尺度变化对绕射系数的影响,本文基于MIKE21-BW模型,数值模拟研究了入射波为不规则波时人工岛尺度不同对其绕射系数的影响。通过数值结果与Briggs物理模型试验结果进行了对比,结果吻合较好,验证了模型在研究波浪绕射问题上的适用性。在未考虑结构物沿波浪传播方向尺度对绕射系数的影响时,将数值结果与《海港水文规范》(JTS145-2-2013)规范结果比对,结果差异较小;本文采用上述模型模拟了结构物沿波浪传播方向7种不同尺度时的波浪绕射情况,分别是0.5Ls,Ls,2Ls,3Ls,4Ls,5Ls及6Ls,通过对不同尺度时的波浪绕射系数变化的分析,得到结果:结构物尺度在0.5Ls^2Ls范围内时,绕射系数随着结构物尺度的增大而变大;结构物尺度在3Ls^6Ls范围内时,绕射系数随着结构物尺度的增大而减小;在人工岛岛壁附近和其掩护区内绕射系数变化较明显;人工岛结构物尺度变化对绕射系数值有影响。文中给出了不同尺度人工岛绕射系数等值线图,可为工程设计中绕射波高确定提供参考。
Artificial island is a large structure in coastal engineering.The determination of design wave height has a close relation with wave diffraction.Although the Code of Hydrology for Sea Harbor(JTS145-2-2013)proposes a method to calculate the height of diffracted wave in shield region of coastal structure,the Code's method does not consider the effect of structure scales along wave propagation direction.In fact,the wave diffraction coefficients differ in the shield area due to the change of structure scale.In this paper,in order to study the wave diffraction coefficients of artificial island with different scales,MIKE21-BW model is employed to simulate the wave field with different structure scales.The isolines of diffraction coefficients in the shield area with different scales of artificial island are drawn based on the simulated results.The wave diffraction coefficients of artificial island with different scales are compared with experimental data as well as the results obtained by the Code's method.The effects of structure scales to diffraction coefficients of the shield region are then analyzed.MIKE21-BW model is an efficient model to study the combined effects of most wave phenomena,including shoaling,refraction,diffraction,partial refection and transmission and so on.The model includes two types of the Boussinesq equations,i.e.,the enhanced Boussinesq equations and the classical Boussinesq equations.In this paper,the enhanced Boussinesq equation is used.In simulating,conditions of the incident wave are supposed the same as Briggs' physical experiment and the Code's,respectively.The values of diffraction coefficients obtained by simulation agree well with experimental data,while,the values obtained by simulation with no consideration of structure scales along wave propagation direction differ quite small from results by the Code's method.The comparison results can verify the applicability of BW model for this study.In order to study the effect of structure scales along wave propagation,this paper simulates 7 cases of different structure scale,i.e.,the length of artificial island along wave propagation is 0.5LsLs,2Ls,3Ls 4Ls 5Ls and 6Ls,respectively.The following results are then obtained from the simulation:(1)Diffraction coefficients become bigger with the increase of scales from 0.5Ls to 2Ls;(2)Diffraction coefficients become slightly smaller with the increase of scales from 3Ls to 6Ls;(3)Diffraction coefficients vary relatively obvious in the area near island and island-shielded region;(4)The scales of artificial island has definite effect on values determination of diffraction coefficients.In this paper,the isolines of diffraction coefficients with different island scales are given,which can be references for calculating the diffracted wave height.
出处
《中国海洋大学学报（自然科学版）》
CAS
CSCD
北大核心
2018年第2期96-104,共9页
Periodical of Ocean University of China
基金
山东省自然科学基金项目(ZR2013EEZ002)资助~~
关键词
BW模型
人工岛
绕射系数
尺度
数值模拟
BW model
artificial island
diffraction coefficients
scales
numerical simulation
