Wave runup on a concentric twin perforated circular cylinder     

K. Vijayalakshmi  S. Neelamani  R. Sundaravadivelu  K. Murali 《Ocean Engineering》2007,34(2):327-336

The regular wave interaction with a twin concentric porous circular cylinder system consisting of an inner impermeable cylinder and an outer perforated cylinder was studied through physical model and numerical model studies. The experiments were carried out on the twin concentric cylinder model in a wave flume to study the wave runup and rundown at the leading and trailing edges of the perforated cylinder. It was found that the maximum wave runup on the perforated cylinder is almost same as the incident wave height. The experimental results were used to develop the predictive formulae for the wave runup and rundown on the perforated cylinder, which can be easily used for design applications. The wave runup profiles around the perforated cylinder for different values of ka and porosities were studied numerically using Green's Identity Method. The results of the numerical study are presented and compared with the experimental measurements.  相似文献   

SAS测量水体表观光学参数的方法     

李铜基  陈清莲 《海洋技术学报》2003,22(1):10-13,57

SeaWiFS航空模拟器（SAS）是专门为在水面之上测量水体表观光学参数的现场设备。文章在介绍SAS现场测量以及数据处理基本方法的基础上，分析了2002年黄海试验SAS的应用效果，并与剖面法测量数据进行了比对。  相似文献   

中国海区区域地质编图中重磁图的编制方法     

张训华 《海洋地质与第四纪地质》1994,14(4):95-100

本文简要介绍了局控项目《中国海区１∶５０万区域地质编图（大连幅）》重力异常图、磁力异常图的编制过程，给出了一种以计算机为手段、实现编图自动化的新方法，并分析了该方法与以往编图方法的不同和优点，以国际分幅在中国海区开展区域地质编图尚属首次，在既无海区地质调查规范，又无海区地质调查编图规范的情况下，这一工作无异具有开创性。从理论上系统总结出一套切实可行的编图方法，对于编制中国海区区域地质调查编图规范以  相似文献   

合浦珠母贝卵子电击脉冲参数的初步研究     

喻达辉  贾晓平  陈素文  李夏  朱嘉濠 《海洋科学》2005,29(8):15-19

运用电脉冲转基因仪对合浦珠母贝卵子进行电脉冲处理以优化电穿孔法转基因的电击参数。实验中调制百分比：100％；脉冲间隔：1．0s：电极距离：2mm；脉冲个数：5个，参数保持不变。用不同的电脉冲参数组合（脉冲电压100-400V、脉冲持续时间0．5～3．0ms、脉冲频率10～50kHz，共28个组合）对卵子电击，然后加入精子进行授精，统计各组受精率和孵化率，以受精率和孵化率达到50％以上为衡量指标。结果表明，合浦珠母贝卵子对低脉冲频率和高电压非常敏感，当频率低于20kHz或脉冲电压高于400V时对卵子损伤较大。脉冲持续时间对其影响不大，适应范围较宽。优化的转基因电击脉冲参教组合为：脉冲电压1.0kV／cm，脉冲持续时间20ms，脉冲频率50kHz，或者脉冲电压1．5kV／cm，脉冲持续时间1．5ms，脉冲频率50kHz。  相似文献   

A time-varying parameter model of a body oscillating in pitch     

A.P. McCabe  G.A. Aggidis  T.J. Stallard   《Applied Ocean Research》2006,28(6):359-370

Among the assumptions upon which linear time-invariant models of floating bodies are based is that the body motions are so small that any change in the body’s angular position can be disregarded. However, it is often a major design requirement of a wave energy conversion device that the response amplitude is large, thereby invalidating one of the assumptions of the linear model. In particular, the immersed geometry of a body undergoes considerable variation when it is moved in pitch. With regard to this we investigate the difference in performance between a quasi-linear model in which the change of immersed surface is modelled by time-varying parameters and a basic linear model in which the immersed surface is time-invariant. The time-varying parameter model is realized by interpolation between the appropriate parameter values of a set of linear time-invariant (LTI) models derived for the different immersed surfaces that occur at discrete body displacements. It is shown that the responses predicted using the time-varying parameter model are closer to those measured experimentally than those of a standard frequency-domain model. Particular improvement occurs when the responses are large, such as at or near the resonance frequency. A problem which may limit the general use of the model is also discussed.  相似文献   

海洋水色卫星遥感器特性参数探讨     

于连生 《海洋技术学报》2001,20(2):76-80

为了评价海洋水色卫星遥感器特性参数的优劣，确定仪器的计量特性及其使用价值，准确的理解和科学的定义仪器的特性参数是非常重要的。作者曾有幸参加了海洋水色卫星的立项论证工作，本文就作者的一些工作体会，对海洋水色卫星遥感器的特性参数作初步探讨。  相似文献   

西太平洋暖池区海—气通量计算分析   总被引：4，自引：0，他引：4  

徐天真  陈伯海 《中国海洋大学学报(自然科学版)》1993,(Z2)

用J.Launiaimen和T.Vihma提出的近地面层湍流通量计算方法,对我国在1992年11月至1993年2月TOGA—COARE—IOP实验中所获资料计算处理。得出所在站位的海一气间显效、潜热及动量通量。指出西大平洋暖池海区游热通量与显效通量之比为10.14:1;风速大于8m/s后各通量随风速的变化率明显增加;动量与热量的块体通量系数Cd和Ce,h随风速变化有相似的规律;Monin—Obukhov大气稳定度参数Z/L与△T/U_(10)之间有较好的统计关系。  相似文献   

Validation and Improvement of Satellite-Derived Surface Solar Radiation over the Northwestern Pacific Ocean     

Kawai  Yoshimi  Kawamura  Hiroshi 《Journal of Oceanography》2005,61(1):79-89

The purpose of this study is to validate and improve satellite-derived downward surface shortwave radiation (DSSR) over the northwestern Pacific Ocean using abundant in situ data. The DSSR derivation model used here assumes that the reduction of solar radiation by clouds is proportional to the product of satellite-measured albedo and a cloud attenuation coefficient. DSSR is calculated from Geostationary Meteorological Satellite-5/Visible Infrared Spin-Scan Radiometer data in 0.05° × 0.05° grids. The authors first compare the satellite DSSR derived with a cloud attenuation coefficient table determined in past research with in situ values. Although the hourly satellite DSSR agrees well with land in situ values in Japan, it has a bias of +13∼+34 W/m² over the ocean and the bias is especially large in the low latitudes. The authors then improve the coefficient table using the ocean in situ data. Usage of the new table successfully reduces the bias of the satellite DSSR over the ocean. The cloud attenuation coefficient for low-albedo cases over the ocean needs to be larger in the low latitudes than past research has indicated. Daily and hourly DSSR can be evaluated from the satellite data with RMS errors of 11–14% and 30–33%, respectively, over a wide region of the ocean by this model. It is also shown that the cloud attenuation coefficient over land needs to be smaller than over the ocean because the effect of the radiation reflected by the land surface cannot be ignored.  相似文献   

水产饲料膨化机设计刍论     

徐钟良  陈启发 《台湾海峡》2001,20(Z1):207-211

据开发应用水产饲料膨化机实践，初步论述了膨化机生产能力与动力匹配，螺杆设计参数长径比，物料在腔内滞留时间，膨化腔设计及其温度调控，并提出改进设计的见解.  相似文献   

Baroclinic Buoyancy-Inertia Joint Stability Parameter     

Hideo Kawai 《Journal of Oceanography》2005,61(2):235-246

At present, the barotropic buoyant stability parameter has been derived from a vertical virtual displacement of a water parcel. The barotropic inertial stability parameter in the eccentrically cyclogeostrophic, basic current field was derived in 2003 from a horizontal cross-stream virtual displacement of a parcel. By expressing acceleration of a parcel due to a virtual displacement, which is arbitrarily sloping within a vertical section across the basic current, in terms of natural coordinates, we derived the vertical component of baroclinic buoyant stability parameter B ₂ ², the horizontal component of baroclinic inertial stability parameter I ₂ ², the baroclinic joint stability parameter J ², its buoyant component B ² and its inertial component I ². B ² is far greater than I ₂ ², and when neglecting relative vorticity except for vertical shear, a downward convex curve of J ² plotted against the slope of a virtual displacement follows a trend of B ² curve. If a parcel displaces along a horizontal surface or an isopycnal surface, however, B ² vanishes, and J ² becomes equal to I ². Actual parcel is apt to displace not only along the bottom slope, but also along the sea surface and an isopycnal interfacial surface, which is approximately equivalent to an isentropic surface, preferred by lateral mixing and exchange of momentum. Such actual displacement makes B ² vanishing, and grants I ² an important role. The present analysis of I ² examining effects due to curvature and horizontal and vertical shear vorticities are useful in deepening our understanding of baroclinic instability in actual oceanic streams.  相似文献