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Lateral Dynamic Analysis and Motion Control of a Jet Trencher in ocean currents

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Journal of Harbin Institute of Technology(New Series) 2017年第1期24卷 26-31页

作者： Xiang Li Tao Wang Min Zhao Tong Ge State Key Laboratory of ocean Engineering Shanghai Jiao Tong UniversityShanghai 200240China

In order to control the lateral motion of a jet trencher which is important for stable trenching operation,the oscillation characteristics of the jet trencher are researched. The jet trencher is simplified into a single degree of freedom model with restoring and damping force. The nonlinear mathematical model of the trencher laterally oscillating in ocean currents is established,and its approximate analytical solution is *** show that the analytical solution has small differences with numerical solution based on the fourth-order Runge-Kutta method and can effectively describe the underwater oscillation. A double-loop PID controller is designed to control the lateral motion displacement of the trencher to return to the center of the pipeline route which is effective and robust for the propulsion system.

关键词： trencher dynamic model analytical solution double-loop control ocean currents

Modeling and simulation of GNSS-R signals with ocean currents

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Modeling and simulation of GNSS-R signals with ocean current...

An Analysis of Observed ocean currents Data and Numerical Simulation in the Offshore Area of Jiaonan

第十一届中国卫星导航年会

作者： Bowen Li Baoguo Yu Lei Yang Dongkai Yang Hua Han School of Electronics and Information Engineering Beihang University State Key Laboratory of Satellite Navigation System and Equipment Technology The 54th Research Institute of China Electronics Technology Group Corporation College of Information Science and Engineering Shandong Agricultural University

In recent years, with the development of Global Navigation Satellite System(GNSS), GNSS reflectometry(GNSS-R) has become a new method in the field of remote sensing. And the simulation of the GNSS-R r

关键词： GNSS reflected signals ocean currents modeling simulation

来源： cnki会议 cnki会议 cnki会议评论

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Marine Science Bulletin 2006年第2期8卷 1-11页

作者：刘伟峰孙英兰张学庆中国海洋大学环境科学与工程学院青岛266003

Based on the diurnal consecutively observed data in the offshore area of Jiaonan in 2005, the paper tries to make a preliminary analysis of the specificity of ocean currents, tidal current property and residual current property in the area in observing dates. Then on the basis of observed data analysis and by employing the split-step method, the paper conducts a numerical simulation of the tidal current field, which can show the M2 tidal constituent tidal wave system, current ellipse distribution, maximum current velocity distribution and time-dependent current field. The calculated results agree well with the observed data, which can on the one hand reflect the basic specificities of temporal and spatial distribution of the M2 tidal constituent current field to some extent, and, on the other hand, offer more information about the hydrodynamic condition. So the paper would provide a scientific basis for the making of sea environment protection plans in the offshore area of Jiaonan under certain conditions.

关键词： ocean currents observed data numerical calculation Jiaonan

A 2D numerical ocean model on the Coriolis and wind stress effects using Stochastics

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Theoretical & Applied Mechanics Letters 2021年第4期11卷 224-229页

作者： Sudhakar Matle Department of Mathematcs VIT-AP UniversityAmaravati-522237India

ocean basin is modeled as a two-dimensional closed,bounded domain in which the fluid flow is governed by the complex partial differential equations in the flow *** in view that the ocean currents are non-viscous,no normal flow conditions are used at the basin *** parameters investigated here are:Coriolis parameter,wind stress coefficient,and *** differential equations in time scales are solved by deterministic and stochastic *** results concluded that streamlines are symmetric about stagnation point(no flow)for 0

关键词： ocean currents Stability Bi-furcation Stochastic control Time scales

Impacts of Different Dynamic Factors on the Saltwater Intrusion in the Northern Branch of the Yangtze Estuary

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China ocean Engineering 2019年第6期33卷 673-684页

作者： WANG Jin-hua ZHANG De-bin ZHANG Wei-sheng ZHANG Jin-shan State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering Nanjing Hydraulic Research InstituteNanjing 210029China College of Harbor Coastal and Offshore EngineeringHohai UniversityNanjing 210098China

A 3-D baroclinic numerical model is established to study the temporal and spatial distribution of salinity in the Northern Branch(NB) of the Yangtze Estuary(YE) in response to river runoff, wind and currents. The idealized,process-oriented studies show that the lower river runoff in the dry season is the main driving factor for the spilling over from the NB to the Southern Branch(SB). The NB takes longer time to get in dynamic stable state compared with the SB, as the runoff transfers from the wet season to the dry season. The vertical stratification intensity of the NB has obvious periodic phenomena in the dry season, and the stratification strength is enhanced under the action of low runoff and north wind, which further weakens the vertical transport of water. Momentum balance analysis suggested that the landward net flux increases when considering the influence of the moderate north wind, and the landward flux will enhance if considering the boundary current during the spring tide. With the influence of the boundary current, increases the average salinity of the NB, as well as the intrusion degree from the NB to the *** indicates that the nearshore ocean current of the Yellow Sea is an important factor affecting the saltwater intrusion in the NB of the YE.

关键词： Yangtze Estuary saltwater intrusion ocean currents vertical stratification FVCOM

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黄河在这里入海

EXPERIMENTAL STUDY ON BED-LOAD SEDIMENT TRANSPORT IN IRREGULAR WAVE-CURRENT COEXISTENT FIELD

绿色中国B版 2013年第10期 28-35页

作者：耿国彪刘月良

谈到黄河，人们自然而然就会想到悠久的中华文明。在黄河的发源地青海省玛多县有两个美丽的湖泊湿地扎陵湖与鄂陵湖，它们为下游的黄河提供着源源不断的生命之水，也成就了5000年生生不息的中华文明。行程5464公里的黄河，在青海发源地... 详细信息

谈到黄河，人们自然而然就会想到悠久的中华文明。在黄河的发源地青海省玛多县有两个美丽的湖泊湿地扎陵湖与鄂陵湖，它们为下游的黄河提供着源源不断的生命之水，也成就了5000年生生不息的中华文明。行程5464公里的黄河，在青海发源地还是一盆清水，但穿过黄土高原后变得浑浊。浑浊的黄河夹杂着黄土高原的大量泥沙，在山东东营入海。在黄河入海口，不断沉积的泥沙形成了我国最年轻的湿地--黄河三角洲。　　湿地被称为“生命的摇篮”、“地球之肾”和“鸟类的乐园”，与人类生存、繁衍、发展息息相关，是自然界中生物多样性最丰富的生态系统，也是人类最重要的生存环境之一。湿地生物资源丰富，虽然湿地覆盖地球表面仅为8.6%，却蕴藏着地球上20%的已知物种。它既是陆地上的天然蓄水库，又是众多野生动植物资源特别是珍稀水禽的繁殖和越冬地。

关键词：黄河三角洲 ocean currents 湿地生物资源中华文明黄土高原野生动植物资源发源地地球表面生物多样性黄河入海口生态系统生命生存环境青海省泥沙浑浊湖泊湿地自然界扎陵湖越冬地

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Journal of Hydrodynamics 2000年第2期12卷 42-53页

作者： Wu, Yongsheng Qin, Chongren Hu, Mei Tianjin Univ Tianjin China

In order to evaluate bed-load sediment transport in an irregular wave-current coexistent field, a series of experiments were completed in laboratory with an irregularly oscillating tray, which is designed to simulate the irregular wave-current coexistent field. The initial motion of sediment and the rates of transport over flat horizontal bed were tested. Comparison between experimental results of initial motion and modified Shields curve indicates that the Shields curve is still valid for the case of irregular wave-current coexistent field. Analysis of flow regime shows that initial conditions fall within smooth-turbulent transitional region. The results of transport rate show that net sediment transport rate can be expressed approximately as the function of the maximum bottom shear stress and mean shear stress. A dimensionless formula is proposed on the basis of the mechanisms of waves erode sediments and tides transport sediments.

关键词： Flow of water ocean currents Oscillations Shear stress Water waves

SIMULATION STUDY OF IMAGING OF UNDERWATER BOTTOM TOPOGRAPHY BY SYNTHETIC APERTURE RADAR

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Journal of Hydrodynamics 2001年第3期13卷 57-64页

作者： Ma, Yi Zhang, Jie First Inst. of oceanography State Oceanic Administration Qingdao 266061 China

Interaction between current and underwater bottom topography modulates roughness of the sea surface, which in turn yields variation of the radar scattering echo. By using the mechanism, this paper presents a simulation model for Synthetic Aperture Radar (SAR) imaging of underwater bottom topography. The numerical simulations experiments were made using the Princeton ocean Model (POM) and analytical expression theory of SAR Image in Mischief sea area. It is concluded that the SAR image is better visual when water depth of underwater bottom topography is shallow or gradient of underwater bottom topography is high.

关键词： Numerical analysis ocean currents Simulation Synthetic aperture radar Underwater imaging Underwater structures

SEASONAL VARIATIONS OF CIRCULATION AND SUSPENDED MATTER TRANSPORT IN THE YELLOW AND EAST CHINA SEAS

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Journal of Hydrodynamics 2001年第4期13卷 8-13页

作者： Pang, Chong-Guang Bai, Xue-Zhi Hu, Dun-Xin Inst. of oceanology Chinese Acad. of Sci. Qingdao 266071 China

The Princeton ocean Model (POM) was modified and used to study the monthly mean circulation in the Yellow Sea and the East China Sea. The calculated results showed almost all major characteristics of the circulation system and their seasonal evolutions. Offshore branch and inshore branch of the Taiwan Warm Current derived from the two sides of the Taiwan Island vary significantly in different seasons. The Tsushima Warm Current is a multi-source current, and especially in winter, mid-shelf water is its main source. The Yellow Sea Warm Current (YSWC) is the strongest in winter, and a part of the YSWC water always adds into the Tushima Warm Current through the north and south sides of the Cheju Island. The calculated thermal structures showed distinct path of the YSWC in winter and the position and scope of the Yellow Sea Cold Water Mass in summer. Based on the circulation simulation, suspended matter transport was modeled numerically by adding its governing equation into the POM. Simulated results on the temporal and spatial distribution of total suspended matter concentration revealed and further proved that seasonal characteristics of suspended matter transport are: storage in summer and autumn, transport in winter and spring in the Yellow and East China Seas. Shelf circulation plays a crucial role in long-term suspended matter transport.

关键词： Computational fluid dynamics Computer simulation ocean currents Sediment transport