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1.
5kW 后弯管波力发电装置的研究 总被引：2，自引：1，他引：1
在造波水槽内对后弯管浮体模型进行了波能转换性能的试验研究。通过对比试验,选定了最佳浮体模型——前方后圆浮室后伸型后弯管浮体。波能转换效率达ηＡ＝ ７３．３％ 。给出了该浮体模型的性能曲线及其无因次特性。测定了该模型最大锚泊力Ｆｍａｘ随浮体参数的变化规律。设计制造了５ｋＷ 后弯管波力发电浮体。该机组采用０．８ｍ 直径的对称翼透平和无刷爪极发电机,输出直流电。采用单点锚泊系统,在珠江口桂山岛西南面海域进行海上试验。实测数据表明,海上试验瞬时功率大于５ｋＷ,超过机组设计额定值。 相似文献
2.
对并联式后弯管波力发电浮体模型的波能转换性能和锚泊力进行了试验研究。结果表明并联式后弯管浮体模型的最佳响应周期基本不变，各单元浮体性能略有差异，位于中间的单元浮体性能略低于两侧的浮体，波能转换性能随浮体数量增加而下降，多点系泊使并联式后弯管装置效率提高。并联式后弯管波力发电装置采用标准化单元设计，灵活组成不同装机容量的装置，将大大降低锚泊系统、海底电缆系统的费用。 相似文献
3.
多点系泊下后弯管波力发电浮体模型试验研究 总被引：1，自引：5，他引：1
在大型造波水池中，对最佳后弯管浮体模型3－3，进行了多点系泊下浮体模型试验研究。测定了该模型在不同系泊条件下，气室平均输出气流功率随波周期的变化曲线NA－T，最大锚泊力与入射波高之比随波周期的变化曲线Fmax/Ho-T和最大纵荡距离与入射波高Ho之比随波周期变化曲线Xmax/Ho-T。选定L型链三点系泊为最佳系泊方案。进行了不同喷嘴比的性能试验和不类来波方向的试验，测定了浮体波能转换性能、最大锚泊力、最大纵荡距离随来波方向的变化。 相似文献
4.
箱式超大型浮体在非均匀海洋环境下的水弹性试验 总被引：2，自引：4，他引：2
超大型浮体(Very Large foating Structure，VLFS)作为人类开发海洋的前沿基地，正在成为世界各国海洋工程界研究的一个热点。由于超大型浮体覆盖的面积比普通的船舶和海洋结构物要大很多，其首尾两端所处的海洋环境可能有显著的差异，因此必须考虑非均匀海洋环境对其水弹性性能的影响。介绍了国内首次进行的箱式超大型浮体在非均匀海洋环境中的水弹性试验，对非均匀海洋环境、超大型浮体的水弹性性能以及两者相互之间的关系进行了研究。 相似文献
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本文根据有关单位提出研制大型波力发电灯浮标的使用要求,经计算,提出两个不同直径的浮体方案,每个方案具有浮体排水量、中心管长度、喷嘴比和气室高度等四个可变参数,共组成162个模型试验方案,在水池中进行规则波的优化试验。模型试验表明,排水量为8吨、浮体直径为3.6米、中心管长度为4米、喷嘴比为200和气室高度为2.5米的方案,具有超过设计要求的输出功率,且满足最佳频响在3秒左右的要求.同时,根据试验结果,也讨论分析了浮标各参数对中心管气室功率的影响,不同的 H/λ比值对浮标气室性能的影响,对今后设计大型波力发电灯浮标有参考作用. 相似文献
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波能装置-浮式防波堤是将浮式防波堤与波能转换装置集成，兼具防波消浪和捕获波浪能的集成装置，能够有效降低单一功能波能转换装置的成本。研究者们提出了许多波能装置-浮式防波堤的结构型式，其中非对称式浮体结构相比于对称式浮体结构，在单向入射波的水动力性能方面拥有一定的优势。本文针对导桩锚泊的非对称式方箱-三角形挡浪板和方箱-垂直挡浪板两种浮体结构型式，通过数值模拟的方式，对比分析其水动力特性和波能俘获特性。数值模型基于黏性流体理论，以Navier-Stokes方程为控制方程，并采用VOF方法和浸没边界法求解自由面边界和流固耦合作用，探究不同入射波周期、水深和浮体排水条件下集成装置水动力性能（消波特性、能量耗散特性和波能俘获特性）变化趋势。结果表明，在近岸波浪条件下（5～8 s），垂直挡板型式集成装置适用于较小周期波浪（5～6 s），而三角挡板型式集成装置适用于较大周期波浪（6～7.5 s）。随着水深增大，波能俘获比总体上呈现缓慢增长的趋势。在主浮体吃水相同的情况下（排水量不同），两种结构的透射系数基本一致；而在排水量相同（主浮体吃水不同）的情况下，垂直挡板结构型式的防波效果更好，三角挡板结构型... 相似文献
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以浮式两级缓冲防撞系统为研究对象,介绍其工作原理,利用动力学分析软件LS-DYNA构建了碰撞模型并进行了仿真计算,依据仿真结果完成了以阻尼索组与浮体结构构型为主要内容的防撞系统设计。研究确定了阻尼索组的布置位置、材料及数量,为浮体内部结构构型设计了7种比选方案,分别对5 000 t船舶撞击浮体前梁和侧梁的动态过程进行了仿真分析,对比了不同方案及不同板梁厚度下的接触力。研究结果表明:浮体内部构造若选用板梁厚度12 mm的方案6设计,则碰撞发生时浮体前梁和侧梁分别可以稳定地提供10.4 MN和7.9 MN的均值力,以及11.5 MN和8.9 MN的峰值力,设计浮体能够满足整体刚度要求,防撞系统符合双保护原则。防撞系统及浮体结构构型设计为下一步全面开展船舶撞击防撞系统后的动力学响应分析奠定了基础。 相似文献
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超大型浮式结构物是一种新型海上结构,浮体结构的不同构型对水动力性能有着较大的影响,而合理可靠地预报波浪载荷是保证海洋结构物设计合理和安全运营的基本前提。基于设计波法,采用莫里森公式和势流理论相结合的方法,对纵向浮筒和横向浮筒两种不同构型的超大型浮式结构物进行水动力分析和波浪载荷长期预报并进行对比分析。研究结果表明:横向浮筒超大型浮体纵荡运动相应幅值比纵向浮筒超大型浮体小很多;纵向扭转为纵向浮筒和横向浮筒超大型浮体最危险工况,其次是垂向弯矩工况;且横向浮筒超大型浮体的垂向弯矩也是较危险的工况。分析结果可为超大型海上浮式结构物的结构设计提供相关合理可靠的理论依据。 相似文献
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后弯管式波力发电装置作为一种漂浮式振荡水柱式装置,具有可靠性强、安装维护方便、工作地点灵活的特点。本文在前人研究基础上,以10kW级后弯管式漂浮型发电装置为研究对象,以装置的水动力学性能为主要研究内容,以气室内相对波高作为主要表征参数,通过断面水槽水工物理模型试验,考察了气室内水柱振荡幅度与入射波波高和入射波周期之间的关系,分析了气室完全开敞、输气管添加负载以及弯管横管长度对气室内水柱振荡的影响,为进一步的大功率装置设计与试验提供了理论依据。 相似文献
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Arne Schnack-Friedrichsen Angela M. Davis Jim D. Bennell Dei G. Huws 《Marine Georesources & Geotechnology》2001,19(4):221-243
The interdependence between the seismo-acoustic properties of a marine sediment and its geotechnical/physical parameters has been known for many years, and it has been postulated that this should allow the extraction of geotechnical information from seismic data. Though in the literature many correlations have been published for the surficial layer, there is a lack of information for greater sediment depths. In this article, a desktop study on a synthetic seafloor model illustrates how the application of published near-surface prediction equations to subsurface sediments (up to several tens of meters burial depth) can lead to spurious predictions. To test this further, acoustic and geotechnical properties were measured on a number of sediment core samples, some of which were subjected to loading in acoustically-equipped consolidation cells (oedometers) to simulate greater burial depth conditions. For low effective pressures (representing small burial depths extending to around 10 meters subsurface), the general applicability of established relationships was confirmed: the prediction of porosity, bulk density, and mean grain size from acoustic velocity and impedance appears generally possible for the investigated sedimentary environments. As effective pressure increases through, the observed relationships deviate more and more from the established ones for the near-surface area. For the samples tested in this study, in some instances increasing pressure even resulted in decreasing velocities. There are several possible explanations for this abnormal behavior, including the presence of gas, overconsolidation, or bimodal grain size distribution. The results indicate that an appropriate depth correction must be introduced into the published prediction equations in order to obtain reliable estimates of physical sediment properties for greater subsurface depths. 相似文献
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Shigehisa Nakamura 《Marine Geodesy》2000,23(1):55-61
Specific properties of the interannual sea level variations and annual tides in the Northwestern Pacific were studied. Several tide stations were monitored. The monthly mean sea level for the year of 1995 was analyzed at each tide station. A seismic event in 1995, some tectonic activity around the subject area, and the Kuroshio (the oceanic western boundary current) may possibly contaminate results which would have occurred from the astronomical annual tide alone. 相似文献
13.
The effect of different fixation and storage protocols on the flow cytometric (FCM) simultaneous analysis of bacterioplankton and phytoplankton in coastal seawater samples (Mediterranean coastal lagoons) was investigated. FCM measurements (cell number, fluorescence and scatter characteristics) were obtained through DAPI staining. Three fixatives [glutaraldehyde (GA), formaldehyde (FA) and paraformaldehyde (PFA)] and two storage (3 months duration) methods (5 °C and −196 °C) were tested. Two dominant populations were detected in studied samples: bacteria and eukaryotic picophytoplankton. Adding fixatives (2% final concentration) appears necessary to obtain FCM exhaustive counts of all the bacteria and phytoplanktonic cells. This was related to the permeation effect of fixatives which allowed a better DAPI staining of the cells. Maximum fluorescence, i.e. optimal staining of the cells was obtained with FA or PFA, and significant lower fluorescences with GA. Fixed samples stored at 5 °C induced rapid cell loss. Only storage in liquid nitrogen of samples fixed with FA or PFA, allows mid-term (≥4 months) preservation of bacteria or picophytoplankton cell numbers, and limited evolution of DAPI-induced fluorescence and scatter characteristics. 相似文献
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《海洋学报(英文版)》2014,(9):F0003-F0003
<正>Acta Oceanologica Sinica(AOS)is a comprehensive academic journal edited by the Editorial Committee of Acta Oceanologica Sinica and is designed to provide a forum for important research papers of the marine scientific community which reflect the information on a worldwide basis.The journal publishes scholarly papers on marine science and technology,including physics,chemistry,biology, 相似文献
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The relationship between the flux of exotic benthic foraminiferal tests (i.e. tests which are supplied from open-sea sources alone) in a tidal inlet and that of bulk sediment was analysed, which can be expressed as two first-order linear equations. According to this relationship, in order to determine net sediment transport directions in the entrance, the test concentration in surficial sediments of the tidal basin can be compared against a ‘ critical level ’. The critical level is determined for the conditions that no net transport of bulk sediment is present within the entrance. If the observed concentration (averaged over the tidal basin) is higher than the simulated critical level, then the net sediment transport is directed to landward. This method is applied to the analysis of net sand transport at Christchurch Harbour, a tidal inlet system located in southern England. In this investigation, concentrations of exotic foraminiferal tests in the surficial sediments of the tidal basin and ebb tidal delta area were obtained from the analysis of sea-bed sediment samples. A series of probable critical levels were calculated based upon the data sets with regard to: (1) sediment discharge from the rivers; (2) magnitude of sediment discharge within the entrance during the ebb; (3) the test concentration outside the harbour; (4) the thickness of the moving layer; and (5) two parameters associated with dispersive processes. The results show that the concentration in the tidal basin sediment is higher than a number of simulated critical concentrations for representative cases. Consequently, the high level of the concentration of exotic benthic foraminiferal tests within the harbour should be explained as a result of landward net transport of sands within the entrance. 相似文献
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Coastal inundation associated with extreme sea levels is the main factor which leads to the loss of life and property whenever a severe tropical cyclonic storm hits the Indian coasts. The Andhra and Orissa coasts are most vulnerable for coastal inundation due to extreme rise in sea levels associated with tropical cyclones. Loss of life may be minimized if extreme sea levels and associated coastal flooding is predicted well in advance. Keeping this in view, location specific coastal inundation models are developed and applied for the Andhra and Orissa coasts of India. Several numerical experiments are carried out using the data of past severe cyclones that struck these regions. The simulated inland inundation distances are found to be in general agreement with the reported flooding. 相似文献
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Rahul Sharma 《Marine Georesources & Geotechnology》2000,18(3):237-250
Observations on seafloor features from subbottom profiling and seabed photography data show that the undisturbed and natural conditions before the benthic disturbance undergo a substantial change after operation of the disturber. The effects can be seen in the form of deep trenches and grooves, formed by the action of the sleds and the pumping of the sediment along its path, as well as sediment piles on either side of the track. Biological traces such as fecal coils, casts, tubes, burrows, and trails get obliterated in the areas of disturbance and resedimentation. The smooth, uniform nature of the seafloor observed in predisturbance phase shows microtopographic changes in and around the disturbed area as a result of sediment excavation and resettlement. Vertical mixing as well as lateral transport of sediment alter the geological, biological, physical, and chemical conditions on the seafloor, which need to be monitored over time to assess the process and the time taken for restoration of environmental conditions. 相似文献
20.
Vance P. Vicente 《Marine Ecology》1989,10(2):179-191
Abstract. Long-term changes in the distributional patterns of commercial sponges ( Spongia spp. and Hippospongia spp.) within the West Indian Region indicates that: 1) commercial sponges had a widespread distribution throughout the whole West Indian Region and were ubiquitous in very shallow water until about the first half of the present century; 2) they were fished commercially not only in the traditional northern Caribbean sites (Florida, Gulf of Mexico, Bahamas) but also in the Greater ( e. g. , Hispaniola, Jamaica) and Lesser Antilles; and 3) they became extinct throughout most of the Lesser Antilles ( e. g. , Puerto Rico, Vieques, St. Thomas) sometime during the first half of this century. Mortalities of spongiids within the Antilles were found to differ from other marine mortalities in that: 1) species disappeared from a large region; 2) species vanished from different habitats and depths; and 3) natural populations never recovered. Species richness patterns suggest that commercial sponge genera ( Spongia and Hippospongia ) evolved under slightly cooler elimatic conditions than those found at present, and that these extinctions occurred as a direct or indirect effect of positive thermal anomalies in sea surface and atmospheric temperatures between 1900–1950. The concept that species diversity is stable on a regional scale is questioned. 相似文献