Automated trinocular stereo imaging system for three-dimensional surface wave measurements     

Justin M. Wanek  Chin H. Wu   《Ocean Engineering》2006,33(5-6):723-747

A novel automated trinocular stereo imaging system (ATSIS) is developed for non-intrusively measuring the temporal evolution of three-dimensional wave characteristics. The system consists of three progressive digital cameras to provide three independent stereo-pairs, i.e. left–right, left–center, and center–right, for accurately estimating depth of a scene. A third camera assists to resolve correspondence problems due to specular reflection on the water surface and provides additional constraints on image matching, dramatically reducing the chance of a mismatch. An oblique configuration for the trinocular system effectively increases spatial coverage, allowing observations of wave phenomena over a broad range of spatial scales. The height resolution is increased with the optical axes of the cameras pointed at an oblique angle with respect to vertical surface wave displacements. A new exterior calibration procedure is developed in this paper to determine the orientation of cameras in the field. Field experiments demonstrate that ATSIS can robustly measure hundreds of matched image points in seconds, allowing fast extraction of the temporal evolution of a three-dimensional surface wave field.  相似文献   

Experimental and Numerical Study of Wave-Induced Long-Shore Currents on A Mild Slope Beach   总被引：4，自引：0，他引：4  

孙涛  陶建华 《中国海洋工程》2005,19(3):469-484

1.Introduction Long shorecurrenthasbecomethesubjectofextensiveworldwideresearchformanyyears.The purposeofthestudyistounderstandandpredicttheprocessesofsedimenttransport,shorelineevolu tionandpollutanttransportinthenear shorezoneundertheactionofwaves.Goda(2001)regarded thesuspendedsedimentastheprincipalloadinsedimenttransportandtheeffectoflong shorecurrents wasemphasized.Theeffectofwavesonpollutanttransportwasstudiedbynumericalmodelandfield experiment(TaoandHan,2002;Rodriguezetal.,1995),andth…  相似文献   

Numerical study of the storm-induced circulation on the Scotian Shelf during Hurricane Juan using a nested-grid ocean model   总被引：2，自引：0，他引：2  

Jinyu Sheng  Xiaoming Zhai  Richard J. Greatbatch 《Progress in Oceanography》2006,70(2-4):233

A nested-grid ocean circulation modelling system is used to assess the upper ocean response of the Scotian Shelf and adjacent slope to Hurricane Juan in September 2003. The nested-grid system consists of a fine-grid inner model covering the Scotian Shelf/slope and a coarse-grid outer model covering the northwest Atlantic Ocean. The model-calculated upper ocean response to Hurricane Juan is characterized by large divergent surface currents forced by the local wind forcing under the storm, and intense near-inertial currents in the wake of the storm. The sea surface temperature (SST) cooling produced by the model is biased to the right of the storm track and agrees well with a satellite-derived analysis. Over the deep water, off the Scotian Shelf, some of the near-inertial energy input by the storm is advected eastward by the Gulf Stream away from the storm track. The hurricane also generates shelf waves that propagate equatorward with the coastline on their right. In comparison with the outer model results, the inner model captures more meso-scale structures, greater SST cooling and stronger near-inertial currents in the study region.  相似文献   

Anisotropy of wind and wave regimes in the Baltic proper   总被引：1，自引：0，他引：1  

Tarmo Soomere 《Journal of Sea Research》2003,49(4):305

The directional distribution of moderate and strong winds in the Baltic Sea region is shown to be strongly anisotropic. The dominating wind direction is south-west and a secondary peak corresponds to north winds. North-west storms are relatively infrequent and north-east storms are extremely rare. Angular distribution of extreme wind speed also has a two-peaked shape with maxima corresponding to south-west and north winds, and a deep minimum for easterly winds. The primary properties of the anisotropy such as prevailing winds, frequency of their occurrence, directional distribution of mean and maximum wind speeds coincide on both sides of the Baltic proper. The specific wind regime penetrates neither into the mainland nor into the Gulf of Finland or the Gulf of Riga.Properties of the saturated wave field in the neighbourhood of proposed sites of the Saaremaa (Ösel) deep harbour are analysed on the basis of the wave model WAM forced by steady winds. The directional distribution of wave heights in typical and extreme storms is highly anisotropic. Remarkable wave height anomalies may occur in the neighbourhood of the harbour sites.  相似文献   

The seasonal circulation of the Glacier Bay, Alaska fjord system     

J.B. Matthews   《Estuarine, Coastal and Shelf Science》1981,12(6)

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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   

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   

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