Measurements of the vertical correlation in turbulence under broken waves     

Claus Pedersen  Rolf Deigaard  James Sutherland 《Coastal Engineering》1998,35(4):231-249

Turbulence measurements have been carried out in the surf zone of a wave flume. The purpose of the measurements is to determine the length scale of the turbulence generated by the wave breaking. The length scale of the turbulence is estimated on basis of the correlation between simultaneous measurements of the vertical turbulent fluctuations, taken at different levels above the bed.  相似文献   

利用沉积物粒度数据反演沉积水动力参数   总被引：5，自引：0，他引：5       下载免费PDF全文

周蒂 《地质科学》1999,34(1):49-58

波罗的海西部达斯浅滩海底沉积物各粒级的空间分布由物源区向外有规律变化,反映出沉积水动力条件的控制作用,反过来也为根据沉积物各粒级的空间分布反演近海底优势水流方向和速度提供了依据。利用沉积水动力经验公式及分选系数梯度、Z统计量等设计了反演优势流向和流速的方法,并应用于该海区,估计了该区海底以上1m的近海底优势水流方向及优势流速。与有限的实测及模拟资料进行对比,估计的海流模式吻合较好,但流速的数值可能总体上偏高,需要用更多实测资料来校正和标定。  相似文献   

斜坡式防波护岸断面形式的实验研究     

王爱群  李春柱 《海岸工程》1999,18(3):17-22

从某一大型工程中的邻海区域江堤加固工程的各种方案比较出发,分析讨论了这类工程结构形式受波浪作用的情况及结构物设计中方案比选的有关问题。  相似文献   

北部湾防城港东湾白骨壤潮滩近底层动力响应台风作用的耗散过程     

黄祖明  戴志军  周晓妍  龙楚琪  冯炳斌  罗杰骏  喜扬洋 《海洋工程》2023,41(2):107-118

揭示极端天气影响的红树林潮滩潮流能量耗散过程是理解生物海岸演变及滨海湿地生态修复工程的核心内容。以北部湾防城港东湾白骨壤红树林潮滩为例,基于声学多普勒流速仪（ADV）获取区域2020年8月连续6天的水动力和白骨壤红树林下垫面植被实测数据,分析白骨壤潮滩近底层动力响应台风“森拉克”的耗散过程。结果表明：1）正常天气涨、落潮期间,自光滩到白骨壤红树林林内近底层湍流动能变化具有潮汐不对称性特征。涨潮期间光滩—白骨壤红树林边缘、白骨壤红树林边缘—林内潮流挟沙能量分别通过泥沙沉降以及搬运泥沙两种方式沿程消耗,落潮期间潮流挟沙能量主要以泥沙净沉降的方式消耗。2）白骨壤通过其潮滩表层向上发育长约10 cm的呼吸根以降低湍流垂向紊动;红树林边缘的枝、叶通过影响水平方向上的水流动力,致使潮流挟沙能耗降低。3）与正常天气比较,台风“森拉克”期间东湾自光滩到白骨壤红树林林内近底层水体流速无明显变化,但流向偏转幅度明显变大。同时湍流动能的耗散率和用以搬运泥沙为主的潮流挟沙能耗亦均增大。  相似文献   

拖曳式多参数剖面测量系统水动力与控制性能研究述评   总被引：12，自引：1，他引：11  

吴家鸣  叶家玮李宁 《海洋工程》2004,22(1):111-120

综述了拖曳式多参数剖面测量系统水动力学研究的最新进展。对拖曳缆绳、拖曳体以及将两者耦合起来所构成的整个系统水动力及控制理论进行述评,分析了各种理论的优缺点从中简要地描述了拖曳式多参数剖面测量系统水动力研究的发展概要。  相似文献   

围填海累积效应对钦州湾水动力环境的影响   总被引：1，自引：0，他引：1  

吕赫  张少峰  宋德海  鲍献文 《海洋与湖沼》2021,52(4):823-833

根据海图资料和卫星影像,确定了钦州湾2004年与2019年两个历史时期的岸线与水深。基于无结构网格有限体积海洋模型建立高精度的水动力模型,分析了近15年来围填海工程的累积效应对钦州湾水动力环境的影响。结果表明:地形与岸线的改变使得钦州湾外湾潮汐振幅减小、茅尾海内潮汐振幅增加;潮流场改变明显,外湾中部流速普遍增加,围填区域潮流减弱明显,但潮流性质未改变,依然为落潮占优;钦州湾纳潮量有所减小,主要发生在外湾区域;而余流减弱,并且出现涡旋,这不利于水体的向外扩散。通过染色实验发现,钦州湾水体半交换周期在有无径流的情况下都明显增长,且在围填海区域水交换能力显著下降。  相似文献   

温泉钙华沉积的影响因素   总被引：2，自引：2，他引：0  

刘海生  周训  张彧齐  海阔  余鸣潇  谭梦如  尚子琦 《中国岩溶》2020,39(1):11-16

钙华是在泉水、河水、湖水、洞穴周围沉积的非海相碳酸钙沉积物。钙华是陆地水循环过程中物质迁移的一种表现形式,研究钙华的形成有助于了解局部水文循环中的物质迁移规律并间接了解古气候与古水文地质条件。部分温泉的泉口附近沉积有形态多样的钙华。本文综述温泉钙华的形成过程、钙华沉积的主要影响因素和它们之间的相互影响关系。水化学条件是钙华沉积的物质基础和必要条件,水动力条件是钙华沉积的充分条件,生物效应对钙华沉积起到加强的作用,沉积环境通过影响水化学条件或水动力条件间接控制钙华的沉积。  相似文献   

大型湖库滨岸带蓝藻水华堆积风险评估——以巢湖为例     

钱瑞  彭福利  薛坤  齐凌艳  段洪涛  邱银国  陈青  陈粉丽  高俊峰  黄佳聪 《湖泊科学》2022,34(1):49-60

淡水湖库富营养化与蓝藻水华是全球性的突出水环境问题,尤其是滨岸带严重蓝藻水华堆积甚至造成了水体黑臭、威胁饮用水安全等严重危害,科学评估滨岸带蓝藻水华堆积风险、精准识别蓝藻水华易堆积区域是水环境管理与研究中亟待解决的关键科学问题.本研究以我国长江中下游的大型浅水富营养化湖泊巢湖为研究对象,依托流域水文与湖泊水动力模拟、遥...  相似文献   

Spatial variation of flow characteristics in a subarctic meandering river in ice-covered and open-channel conditions: A 2D hydrodynamic modelling approach     

Eliisa Lotsari  Tiia Tarsa  Maria Kämäri  Petteri Alho  Elina Kasvi 《地球表面变化过程与地形》2019,44(8):1509-1529

To be able to understand year-round river channel evolution both at present and in the future, the spatial variation of the flow characteristics and their sediment transport capabilities under ice cover need to be detected. As the measurements done through cross-sectional drill holes cover only a small portion of the river channel area, the numerical simulations give insight into the wider spatial horizontal variation of the flow characteristics. Therefore, we simulate the ice-covered flow with a hydrodynamic two-dimensional (2D) model in a meandering subarctic river (Pulmanki River, Finland) in mid-winter conditions and compare them to the pre-winter open-channel low flow situation. Based on the simulations, which are calibrated with reference measurements, we aim to detect (1) how ice-covered mid-winter flow characteristics vary spatially and (2) the erosion and sedimentation potential of the ice-covered flow compared to open-channel conditions. The 2D hydrodynamic model replicated the observed flow characteristics in both open-channel and ice-covered conditions. During both seasons, the greatest erosional forces locate in the shallow sections. The narrow, freely flowing channel area found in mid-winter cause the main differences in the spatial flow variation between seasons. Despite the causes of the horizontal recirculating flow structures being similar in both seasons, the structures formed in different locations depended on whether the river was open or ice covered. The critical thresholds for particle entrainment are exceeded more often in open-channel conditions than during ice-covered flow. The results indicate spatially extensive sediment transport in open-channel conditions, but that the spatial variability and differences in depositional and erosional locations increase in ice-covered conditions. Asymmetrical bends and straight reaches erode throughout the year, whereas symmetrical, smaller bends mainly erode in open-channel conditions and are prone to deposition in winter. The long ice-covered season can greatly affect the annual morphology of the submerged channel. © 2019 John Wiley & Sons, Ltd.  相似文献   

Application research of narrow band Internet of things buoy and surface hydrodynamics monitoring     

Yiqun Xu  Jia Wang  Li Guan 《海洋学报(英文版)》2021,40(8):176-181

This paper applies the narrow band Internet of things communication technology to develop a wireless network equipment and communication system, which can quickly set up a network with a radius of 100 km on water surface. A disposable micro buoy based on narrow-band Internet of things and Beidou positioning function is also developed and used to collect surface hydrodynamic data online. In addition, a web-based public service platform is designed for the analysis and visualization of the data collected by buoys. Combined with the satellite remote sensing data, the study carries a series of marine experiments and studies such as sediment deposition tracking and garbage floating tracking.  相似文献