Internal generation of waves: Delta source function method and source term addition method

In this study, we investigate two internal wave generation methods in numerical modeling of time-dependent equations for water wave propagation, i.e., delta source function method and source term addition method, the latter of which has been called the line source method in literatures. We derive delta source functions for the Boussinesq-type equations and extended mild-slope equations. By applying the fractional step splitting method, we show that the delta source function method is equivalent to the source term addition method employing the energy velocity. This suggests that the energy velocity should be used rather than the phase velocity for the transport of incident wave energy in the source term addition method. Finally, the performance of the delta source function method is verified by accurately generating nonlinear cnoidal waves as well as linear waves for horizontally one-dimensional cases.     

Generation of random waves in time-dependent extended mild-slope equations using a source function method

We develop techniques of numerical wave generation in the time-dependent extended mild-slope equations of Suh et al. [1997. Time-dependent equations for wave propagation on rapidly varying topography. Coastal Engineering 32, 91–117] and Lee et al. [2003. Extended mild-slope equation for random waves. Coastal Engineering 48, 277–287] for random waves using a source function method. Numerical results for both regular and irregular waves in one and two horizontal dimensions show that the wave heights and the frequency spectra are properly reproduced. The waves that pass through the wave generation region do not cause any numerical disturbances, showing usefulness of the source function method in avoiding re-reflection problems at the offshore boundary.     

Wave run-up and overtopping on smooth and rough slopes of coastal structures

A series of hydraulic model tests has been carried out in a glass wave flume to investigate the influences of wave height, wave period, wave steepness, surf similarity parameter, roughness, layer thickness and porosity on wave run-up and overtopping of 1:2 sloped impermeable and permeable breakwaters fronted by a 1:10 gentle, smooth beach slope. The analysis of results involves the correlation between the overtopping energy transfer with the relative wall height and the relationship between wave run-up and overtopping rate. Further, measured wave run-up and overtopping rates are compared with the results given in the Shore Protection Manual (1984), Automated Coastal Engineering System (1992)and results of other investigators.     

河口环流和盐水入侵Ⅱ--径流量和海平面上升的影响

本文利用本序列上篇论文建立的理想河口数值模式,研究径流量和海平面上升对河口环流和盐水入侵的影响.在径流量增大的情况下,口门内表层向海的流速增大,底层向陆的密度流减弱,滞流点下移.口门外侧向口门的密度流增大,上升流趋于增强.口门内盐水入侵减弱,口外盐度减小、冲淡水扩展范围增大.在口门上游北岸底层盐度下降明显,口门处南岸表层盐度下降明显.径流量变化对盐水入侵影响十分巨大.在海平面上升的情况下,拦门沙区域向陆的密度流增强,滞流点上移,表层向海的流动增大.口门内盐水入侵增强,口外盐度增大,冲淡水扩展范围减小.海平面上升对盐水入侵影响十分明显,北岸底层盐度增大尤为特出.     

A note on estimation of the Jacobian elliptic parameter in cnoidal wave theory

A new and simple calculating technique for the Jacobian elliptic parameter is presented in this study. The technique is very useful in generating a train of cnoidal waves in both laboratory and numerical wave tanks. Upon specification of water depth, the wave height and either the wave period or the wavelength, the proposed technique uses the Newton–Raphson method to estimate the Jacobian elliptic parameter directly, without trial and error procedures or look-up in tables. It is shown that the technique provides equally accurate results as the ad hoc methods previously used.     

机载雷达高度计对海况及海面风速的测量研究

运用我国自行研制的ＺＨＧ－１型Ｘ波段机载雷达高度计于１９９５年４月１３日－４月１８日在青岛附近海域进行的海上飞行实验数据，及导出的均方根波高、有效波高、均方根波陡算法模型，得到了上述海况参数值。     

JONSWAP谱和N谱的几个对应特征量间的关系

研究了风浪频谱ＪＯＮＳＷＡＰ谱的峰度因子γ、尖度因子Ｐｊ和Ｎ谱尖度因子ＰＮ，参变量ｐ，ｑ间的关系；并在此关系上给出了由这两种谱计算的几个对应参量间的关系，在使用不同的谱形进行特征量的计算时，应注意不同频谱间的成长因子致性，以免引起计算结果的错误。     

确定连续系统参数的时域方法

提出一种确定连续系统参数的时域方法。该方法利用方波输入和系统稳定性，离析出输出采样信号与结构参数的内在联系，推导出确定连续系统结构参数的算法．指出该算法与辨识方法相结合，可实现对含随机干扰的连续系统结构参数的估计．     

季节内SST和混合层深度变化的模式研究

用Niiler—Kraus类型的混合层积分模式,对TOGA—COARE强化观测期间由《实验3号》科学考察船观测资料得到的混合层深度和SST在季节内时间尺度的变化进行了模式研究。指出:1.混合层耗散参数与较长时间尺度过程风应力的变化存在着比较好的对应关系;2.模式可以较好的对风场和热通量场在季节内时间尺度的变化作出响应,模拟出季节内时间尺度SST的变化;3.Niiler,-Kraus模式在考虑耗散作用后,可用于海洋季节内时间尺度变化的模式研究。     

海水叶绿素α浓度遥感测量的实验研究

本文描述了1989年11月在青岛即墨岙山养殖基地所做的海水叶绿素σ浓度遥感测量的基础实验。该实验获得了高浓度叶绿素α含量的海水反射光谱。该反射光谱的特征波段为:波谷在485nm;波峰在450nm 和535nm;“节点”在572nm.根据该实验数据选取了叶绿素α浓度两种双波段估算模式.分析结果表明;两种模式的精度都在50%以上,且双波段反射率的差值法优于双波段反射率比值法.