Influence of Energy Directional Spread on Wave Spectral Refraction     

Li Yucheng Professor  Dept. of Civil Engineering  Dalian University of Technology  Dalian 《中国海洋工程》1992,(2)

Pierson- Moskowitz Spectrum, JONSWAP Spectrum as well as Bretschneider- Mitsuyasu Spectrum are used in this paper for analyzing the influence of wave energy directional spread on refraction of wave spectrum due to both current and topography of sea bed. The author's calculation indicates that such kind influence on the characteristic value of wave height as well as the average direction of wave energy propagation can not be ignored.  相似文献   

Verification of a VOF-based two-phase flow model for wave breaking and wave–structure interactions     

Phung Dang Hieu  Katsutoshi Tanimoto   《Ocean Engineering》2006,33(11-12):1565-1588

The objective of the present study is to develop a volume of fluid (VOF)-based two-phase flow model and to discuss the applicability of the model to the simulation of wave–structure interactions. First, an overview of the development of VOF-type models for applications in the field of coastal engineering is presented. The numerical VOF-based two-phase flow model has been developed and applied to the simulations of wave interactions with a submerged breakwater as well as of wave breaking on a slope. Numerical results are then compared with laboratory experimental data in order to verify the applicability of the numerical model to the simulations of complex interactions of waves and permeable coastal structures, including the effects of wave breaking. It is concluded that the two-phase flow model with the aid of the advanced VOF technique can provide with acceptably accurate numerical results on the route to practical purposes.  相似文献   

Hilbert transform and its application to modulation of capillary gravity waves     

Yin Zhongbin  Lu Jun  Tian Jiwei 《海洋学报(英文版)》2001,20(3):309-315

INTRODUCFIONlt is well known that the stability and interaction of nonlinear waves lead to modulations ofwavenumber and frequency, as well as arnplitude, with the frequency dePendent on bothwavenumber and arnplitude (Witham, l974; Philips, l98l ). These medulations are not justtheoretical curiossities but have important conSequences in oceanography and meteorology, aswell as naval architecture and ocean engineering (honguer-Higgins, l980).By means of Hilbert transfOrm technique, Melvill…  相似文献   

二阶非线性随机海浪波面高度和波面垂直速度的联合分布     

管长龙 《海洋与湖沼》1997,28(5):503-508

基于Longuet－Higgins提出的非线性随机海浪模型，在二阶近似下通过直接计算联合分布的各阶矩，导出了非线性海浪波面高度和波面垂直速度的联合分布。该分布为非正态，其形式为截断的级数，而非由累积矩母函数方法可能得到的渐近无穷级数。由于非线性的影响，波面高度与波面垂直速度不再相互独立。  相似文献   

Analytical Study on Transmission and Reflection of Non-Linear Shallow Water Waves     

Miao Guoping Liu Yingzhong Professor  Dept. of Naval Architecture  Ocean Engineering  Shanghai Jiao Tong University  Shanghai 《中国海洋工程》1991,(1)

The analytical study is made by using the method of matched asymptotic expansions on the transmission and reflection of solitary waves and cnoidal waves on two-dimensional floating bodies. The solutions give explicitly the variation pattern of the transmitted waves and the characteristics of the reflected waves, including the wave profile, amplitude, phase shift and evolution. The effects of the gap between the body and the sea bottom on the transmission and reflection of those waves are also discussed.  相似文献   

A Spectral Approach for Determining Altimeter Wind Speed Model Functions   总被引：9，自引：0，他引：9  

Dongliang Zhao  Yoshiaki Toba 《Journal of Oceanography》2003,59(2):235-244

We propose a new analytical algorithm for the estimation of wind speeds from altimeter data using the mean square slope of the ocean surface, which is obtained by integration of a widely accepted wind-wave spectrum including the gravity-capillary wave range. It indicates that the normalized radar cross section depends not only on the wind speed but also on the wave age. The wave state effect on the altimeter radar return becomes remarkable with increasing wind speed and cannot be neglected at high wind speeds. A relationship between wave age and nondimensional wave height based on buoy observational data is applied to compute the wave age using the significant wave height of ocean waves, which could be simultaneously obtained from altimeter data. Comparison with actual data shows that this new algorithm produces more reliable wind speeds than do empirical algorithms. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

Diffraction of multidirectional random waves by multiple rectangular submarine pits     

Hong Sik Lee  A. Neil Williams  Bo Hyung Lee  Jeill Oh 《Ocean Engineering》2003,30(1):1287-106

A numerical model is presented to predict the interaction of multidirectional random surface waves with one or more rectangular submarine pits. The water depth is assumed uniform and the method involves the superposition of diffraction solutions based on linearized shallow water wave theory obtained by a two-dimensional boundary integral approach. The incident wave conditions are specified using a discrete form of the Mitsuyasu directional spectrum. The present numerical model has been validated through comparisons with previous theoretical results for regular waves. Good agreement was obtained in all cases. Based on these comparisons it is concluded that the present numerical model is an accurate and efficient tool to predict the wave field around multiple submarine pits and navigation channels in many practical situations.  相似文献   

Nonlinear progressive waves in water of finite depth — an analytic approximation     

Longbin Tao  Hao Song  Subrata Chakrabarti 《Coastal Engineering》2007

An analytical solution using homotopy analysis method is developed to describe the nonlinear progressive waves in water of finite depth. The velocity potential of the wave is expressed by Fourier series and the nonlinear free surface boundary conditions are satisfied by continuous mapping. Unlike the perturbation method, the present approach is not dependent on small parameters. Thus solutions are possible for steep waves. Furthermore, a significant improvement of the convergence rate and region is achieved by applying Homotopy-Padé Approximants. The calculated wave characteristics of the present solution agree well with previous numerical and experimental results.  相似文献   

局地凝结加热对大气赤道波动稳定性的影响(英文)     

Gregory Zhikharev  傅刚  左中道 《中国海洋大学学报(自然科学版)》1993,(1)

利用β平面上大气斜压强迫模式,探讨了局地海表温度异常所造成的非绝热加热影响的赤道小振幅“拦截波”的稳定性。指出当加热函数是半余弦形式时,在加热区大气的反应是局地性的,但这个加热函数的小扰动能产生非局地性的大尺度反应。平均海表温度降低了赤道波动的稳定性。当稍超过临界值时,小尺度海表温度异常有可能使波动不稳定。  相似文献   

Ocean wave transmission by submerged reef—A physical model study     

K.G. Shirlal  Subba Rao  Manu 《Ocean Engineering》2007,34(14-15):2093-2099

Ocean waves can be destructive as steeper waves due to their high energy eroding the sandy beaches. During storm surge or high tide, the water level rises and if large waves occur, they will break closer to the beach, releasing enormous amount of energy resulting in strong currents. This causes heavy loss of beach material due to large-scale erosion. If these waves are made to break prematurely and away from the beach, they can be attenuated so as to reduce beach erosion. The reef, which is a homogeneous pile of armour units without a core, breaks the steeper ocean waves, dissipates a major portion of their energy and transmits attenuated waves. This paper experimentally investigates the armour stone stability of the submerged reef and the influence of its varying distance from shore and crest width on ocean wave transmission.  相似文献