Laboratory Study of the Nonlinear Transformation of Irregular Waves over A Mild Slope     

于博  马玉祥  马小舟  董国海 《海洋工程》2014,28(4):489-500

This paper considers the nonlinear transformation of irregular waves propagating over a mild slope (1?40). Two cases of irregular waves, which are mechanically generated based on JONSWAP spectra, are used for this purpose. The results indicate that the wave heights obey the Rayleigh distribution at the offshore location; however, in the shoaling region, the heights of the largest waves are underestimated by the theoretical distributions. In the surf zone, the wave heights can be approximated by the composite Weibull distribution. In addition, the nonlinear phase coupling within the irregular waves is investigated by the wavelet-based bicoherence. The bicoherence spectra reflect that the number of frequency modes participating in the phase coupling increases with the decreasing water depth, as does the degree of phase coupling. After the incipient breaking, even though the degree of phase coupling decreases, a great number of higher harmonic wave modes are also involved in nonlinear interactions. Moreover, the summed bicoherence indicates that the frequency mode related to the strongest local nonlinear interactions shifts to higher harmonics with the decreasing water depth.  相似文献   

平缓岸坡上波浪破碎的实验研究   总被引：9，自引：0，他引：9  

李玉成  于洋  崔丽芳  董国海 《海洋通报》2000,19(1):10-18

在１／２００的缓坡上进行了规则波与不规则波破碎的实验研究。在本实验条件下,分析了波形的不对称必至波浪破碎指标的影响,并以此对合田良实和Ｎｅｌｓｏｎ关于极平缓坡上规则波破碎指标的分歧作了解释。本文的研究还表明,底坡坡度ｉ、相对水深ｄ／Ｌ。及波形的不对称必至不规则波的破碎指标的影响较小。合田对规则波的破碎指标在不规则波条件下仍然可用,但系数Ａ应取为０．１５。不规则波波长与同周期按线悸理论计算之波长的比  相似文献   

基于非静压模型的波浪空间聚焦研究     

马小舟  马建兴  马玉祥  董国海 《中国海洋大学学报(自然科学版)》2020,50(4):128-135

为研究波浪聚焦特性,分析极端波浪的产生机理,采用非静压模型通过数值模拟的方法对波浪聚焦的影响因素进行了详细研究。本文采用SWASH非静压波浪模型,模型垂向均匀分三层以保证足够的色散精度以及非线性精度来高效准确的模拟波浪在变化地形上的传播。研究发现在最大波浪未发生破碎时,波浪在半圆形凸起斜坡浅滩上传播,波浪聚焦是波高增大的最主要原因。初始kR(波数与浅滩半径乘积)值对波浪在该地形上的聚焦特性有着重要影响。初始kR越大,最大波高位置距聚焦地形坡脚的距离越远。当kR在1.4π~4.05π之间时,随着kR的减小,最大相对波高先增大后减小,当kR=2.45π时,最大相对波高达到极大值,可达2.48倍初始波高。  相似文献   

有限水深下独立波群的能量变化试验研究     

赫岩莉  马玉祥  马小舟  董国海 《海洋工程》2019,37(1):56-63

为了研究独立高斯型波群在中等水深条件下的非线性演化情况,进行了多种波况的物理试验,重点分析了波浪各要素对波群非线性演化的影响。试验结果表明,波陡在波群演化中占主导作用,其次是波群的谱宽,前者引起的非线性主要体现在高阶谐波的能量变化而后者引起的非线性主要体现在自由波能量的变化。频带下移现象只在大波陡情况下才会发生,随着波陡的增加,频带下移发生的相对更早,随着波群的谱变窄,频带下移相对越明显。波陡的增加会使得波群更早的开始分裂。大波陡的波群在演化中会发生破碎,破碎的类型以崩破为主,并且崩破是间歇发生的,连续崩破发生的距离约为1.0～1.5倍波长。此外,破碎引起的能量损耗主要来源于主频和高频成分波,耗散率约10%～18%,平均每个崩破能耗约为初始能量的2%。  相似文献   

关于统筹规划利用土地资源支持省会城市群经济圈发展专题调研报告————系列报道之二     

周莲英  刘祥元  李金良  王大学  许鲁平  董国海  刘殿成 《山东国土资源》2006,22(12):1-7

3发展土地资源保障与支撑能力分析 3．1发展用地预测 以2005年为基期，2020年为目标年，分析未来15年内经济圈发展及用地情况。全省人口总量将在2020年左右达到峰值，也将是土地资源承载力的峰值，因此，分析预测2020年左右的用地需求情况对认识经济圈的土地资源保障与支撑能力具有较强的说服力。  相似文献   

双色波引起的碎波拍的数值研究          下载免费PDF全文

马小舟  董国海  滕斌 《海洋学报》2007,29(6):172-176

碎波拍是指在近岸水域沿海岸线正向传播、周期为0.5~5.0 min的波浪.碎波拍是近岸低频波浪的一种,最早由Munk[1]和Tucker[2]独立观测到并命名.  相似文献   

缓坡上波浪谱的变形及破碎     

李玉成  董国海 《海洋学报》1994,16(5):112-125

在文献[1]中,通过实验分析和理论计算,笔者提出不规则波浪的破碎指标仍可采用合田[2]的相对波高极值(H/d)_b与Michell[3]和Miche[4]的极限波陡指标(H/L)_b.本文利用该破碎指标,分析计算了缓坡上不规则波在水流作用下的谱变形、波高的统计分布以及波浪破碎的概率等,其结果与作者的实验结果符合良好。  相似文献   

Interaction Between Waves and A Comb-Type Breakwater   总被引：2，自引：1，他引：2  

DONG  Guo-hai 《中国海洋工程》2003,17(4):517-526

The characteristics of wave transmission, reflection and energy dissipation of comb-type caisson breakwaters are studied through laboratory physical model tests. Regular and irregular waves, with a wide range of wave heights and periods and a constant water depth, are considered. Different dimensions of each portion of the comb-type caisson breakwater are tested. Empirical formulae for calculating the reduction coefficient k, which is the ratio of horizontal wave force on unit length of the comb-type breakwater to that on unit length of the vertical wall breakwater, and for calculating the reflection coefficient of waves k, are obtained from the measurements. The comb-type caisson breakwater has been found to be very efficient in dissipating incident wave energy and in reducing wave reflection, and has already been used for the construction of an island breakwater in the Dayao Bay of Dalian Port, Liaoning Province, China. Compared with the cost of a common caisson breakwater, about 24. 5% of the investm  相似文献   

Numerical Simulation of Hydrodynamic Behaviors of Gravity Cage in Waves     

赵云鹏李玉成  董国海桂福坤 《中国海洋工程》2007,21(2):225-238

This paper aims at investigation of the dynamic properties of gravity cage exposed to waves by use of a numerical model. The numerical model is developed, based on lumped mass method to set up the equations of motion of the whole cage; meanwhile the solutions of equations are solved by the Runge-Kutta-Verner fifth-order and sixth-order method. Physical model tests have been carried out to examine the validity of the numerical model. The results by the numerical simulation agree well with the experimental data.  相似文献   

Improvements on Mean Free Wave Surface Modeling   总被引：1，自引：0，他引：1  

DONG  Guo-hai 《中国海洋工程》2002,16(4):549-560

Some new results of the modeling of mean free surface of waves or wave set-up are presented. The stream funetion wave theory is applied to incident short waves. The limiting wave steepness is adopted as the wave breaker indcx in the calculation of wave breaking dissipation. The model is based on Roelvink (1993), but the numerical techniques used in the solution are based on the Weighted-Average Flux (WAF) method (Watson et al. , 1992), with Time-Operator-Split-ting (TOS) used for the treatment of the source terms. This method allows a small number of eomputational points to be used, and is particularly efficient in modeling wave set-up. The short wave (or incident primary wave) energy equation is solved by use of a traditional Lax-Wendroff technique. The present model is found to be satisfactory compared with the measurements conducted by Stive (1983).  相似文献