Similarity method for modelling hydroelastic offshore platforms     

C. Shumin  A.S.J. Swamidas  J.J. Sharp 《Ocean Engineering》1996,23(7):575-595

Similarity methods provide a very powerful technique for modelling offshore platforms. Such methods are preferable for situations where the wave-structure interaction process is complex, and its modelling cannot be expressed by rigorous mathematical formulations.In modelling the interaction between waves and an offshore platform, the dynamic properties of the wave and structure must be considered together to determine the similitude parameters. The paper gives details of such an investigation using a frequency response function approach. Three different models, which are termed general, distorted and nondistorted Froudian models, are developed. From the general model, it was found that the velocity scales of the wave and structure could be treated differently. Internal and external force scales could also be different. It is observed then that a restrictive modelling criterion is used when the velocity scale of a structure is obtained from Froudian scale modelling. Furthermore, detailed scales for practical use are developed. The model parameters for an acrylic plastic tripod tower platform with length scales of 1/50 and 1/70 are given, and the accuracy involved among the three models determined for these scales. The sensitivity of the results to slight variations in thickness and Young's modulus are also discussed.  相似文献   

北黄海及其围域地区北北西和北东东向断裂的岩组学     

刘树民 《中国海洋大学学报(自然科学版)》1987,(3)

北黄海位于辽东半岛,山东半岛与朝鲜之间,海域及周围地区广泛发育了北东东向和北北西向断裂,据物探资料,它们控制了中、新生代盆地的成生与发展。我们通过部分同方向断裂的岩组学研究,将岩组动力学分析的观点引进岩组图的解释,获得了几点新认识: (1)显微统计测量得到的信息与宏观构造分析有机地结合起来,是对一个地区进行变形史分析的有效研究方法。 (2)以石英在变形过程中仅能以菱面或锥面为主要滑动面为基础,分析北黄海围域断裂的岩组图形,得出了与宏观一致的结论。 (3)北黄海及周围地区的北东东向和北北西向断裂,在第三纪末改变了一次动力学性质,是起因于太平洋板块运动方向的变更。  相似文献   

Experimental Study on Temperature Response of Different Ranks of Coal to Liquid Nitrogen Soaking     

Liu  Shumin  Li  Xuelong  Wang  Dengke  Zhang  Dongming 《Natural Resources Research》2021,30(2):1467-1480

Natural Resources Research - Liquid nitrogen freeze–thaw has been used in oil, shale gas and coalbed methane exploitation as an efficient fracturing technology. This paper aimed to study the...  相似文献   

松辽盆地徐家围子断陷火山岩裂缝形成机理   总被引：1，自引：0，他引：1  

陈树民  姜传金  刘立  初丽兰  裴明波 《吉林大学学报(地球科学版)》2014,44(6):1816-1826

松辽盆地徐家围子断陷是位于松辽盆地北部深层的半地堑型晚侏罗世-早白垩世伸展断陷,火山岩发育。在已有研究成果的基础上,结合野外露头和岩心观测及镜下研究发现：本区火山岩构造裂缝和溶蚀裂缝都比较发育,具有明显的规律性,多数原生缝被后期的构造应力或溶蚀作用改造成次生缝。本区裂缝形成的控制因素较多,主要有应力、构造、岩性和岩相、溶蚀作用、风化淋滤、构造应力场演化等,其中构造应力场演化、岩性和岩相及风化溶蚀作用是控制裂缝形成的主要因素。构造裂缝以高角度的张扭性和张性缝为主,多为半充填和无充填,具有多期、多方向、组合复杂等特点,是晚侏罗世至新近纪各种地质作用相互叠加的结果。构造通过控制不同构造部位的局部应力场分布来控制裂缝发育程度,沿断裂带存在明显的应力集中,形成裂缝发育带,特别在正断层上升盘、断层端部、背斜轴部等应力集中部位容易形成构造裂缝。有效火山岩油气储层为各类原生孔隙与裂缝的有效组合。由于火山喷发多个旋回叠加,加之风化剥蚀及不整合面的存在,造成裂缝在纵向上发育具有旋回性,溶蚀裂缝主要在不整合面附近发育。在平面上,裂缝主要发育在断裂密集区、断裂交汇部位和背形或向形构造发育的地区。本区处于爆发相和溢流相火山岩的发育区,气孔和裂缝最发育,特别是溢流相的流纹岩中,裂缝和气孔均较为发育,是本区的优质储层最发育区,也是天然气富集区。  相似文献   

松辽盆地中央坳陷滨北地区上白垩统青山口组沉积相与沉积演化   总被引：5，自引：1，他引：4       下载免费PDF全文

赵波  尹淑敏  张顺  林春明  梁江平 《古地理学报》2009,11(3):293-300

通过岩心和测井资料分析,系统地研究了松辽盆地中央坳陷滨北地区上白垩统青山口组的沉积特征;采用单因素分析多因素综合作图法,编制出了研究区上白垩统青山口组各亚段的砂岩含量、暗色泥岩含量和紫红色泥岩含量等单因素图件,在此基础上做出沉积相图,深入分析了研究区沉积演化规律。研究表明,青山口组主要发育三角洲和湖泊2种沉积相,进一步分为三角洲平原、三角洲前缘、滨浅湖和半深湖-深湖4种沉积亚相。从研究区边缘到中心,沉积相类型由三角洲平原亚相渐变为三角洲前缘、滨浅湖和半深湖-深湖亚相;自下而上由半深湖-深湖亚相逐渐变为滨浅湖、三角洲前缘、三角洲平原亚相。青山口组沉积时期可划分为青山口组沉积早期、青山口组沉积中期和青山口组沉积晚期。不同时期、不同构造单元的沉积特征表现各异,从青山口组沉积早期到青山口组沉积晚期,研究区湖盆发育总体表现出规模由大到小的特点。  相似文献   

Impact of water resource exploitation on the hydrology and water storage in Baiyangdian Lake   总被引：4，自引：0，他引：4  

Juana Paul Moiwo  Yonghui Yang  Huilong Li  Shumin Han  Yanmin Yang 《水文研究》2010,24(21):3026-3039

Water resources development and exploitation are critical for a viable and sustainable modern human society. Unfortunately, however, there is a considerable water storage depletion and environmental degradation in especially (semi)‐arid river basins due to the forces of population growth, urbanization, industrialization and intensive agricultural irrigation. Addressing water storage depletion is not only a question of research, but is very much a question of developing appropriate countermeasures to preserve valuable/fragile ecological systems. As one such effort, this study analyzes the hydrology and storage in Baiyangdian Lake as affected by water resources development and exploitation in the Baiyangdian Lake Catchment of Northern China. Three models, WetSpass (Water and Energy Transfer between Soil, Plants and the Atmosphere under quasi‐Steady State), WATBUD (Water Budget) and MODFLOW (USGS three‐dimensional finite‐difference groundwater flow model) were used in combination to simulate the hydrogeologic conditions in the lake catchment for 1956–2008. The model‐calibrated values are in good agreement with the measured values, with R² > 0·8 and RMSE < 10% of measured values. Runoff, the primary source of water for the lake storage, has steadily declined due mainly to multiple dam construction and reservoir impoundments in the headwater valleys and rivers in the catchment. In addition to dwindling runoff, groundwater levels have declined considerably due to over‐abstraction, mainly for agricultural irrigation. Additionally, evaporation or evapotranspiration is increasing in the lake catchment due to rising temperatures. The worsening hydrological conditions, amid the harsh semi‐arid climate, have resulted in considerable depletion of the storage and hydrology of Baiyangdian Lake. Sustainable countermeasures like agricultural water‐saving and infusion of external water (e.g., via by the South–North Water Transfer Project) could be a viable option for preserving not only the hydrology of the lake catchment, but also storage in Baiyangdian Lake. Copyright © 2010 John Wiley & Sons, Ltd.  相似文献   

In Situ FT-IR Observations on NaCl-H2O-D2O Fluids at Temperatures up to 850°C Using Hydrothermal Diamond Anivl Cell     

HU Shumin  ZHANG Ronghu  ZHANG Xuetong 《《地质学报》英文版》2013,87(Z1):242-244

  相似文献   

Spatio-temporal variations in the siphonophore community of the northern South China Sea   总被引：2，自引：0，他引：2  

李开枝  尹健强  黄良民  练树民  张建林 《中国海洋湖沼学报》2013,31(2):312-326

To understand how hydrological and biological factors affect near-to off-shore variations in the siphonophore community,we sampled zooplankton at 82 stations in the northern South China Sea during summer,winter,and spring.Forty-one species of siphonophore were collected by vertical trawling.The species richness of siphonophores increased from the nearshore to offshore regions in all three seasons of investigation,with maximum richness in summer and minimum richness in winter.The abundance of siphonophores was also higher in summer than in spring and winter,concentrated in the nearshore region in the warm season and scattered in the offshore region in the cold season.Four siphonophore groups were classified according to the frequency of occurrence:nearshore,near-offshore,offshore,and tropical pelagic.Among them,the nearshore group had higher abundance nearshore compared with the offshore.The tropical pelagic group had higher species number offshore than nearshore.Spatial and temporal fluctuations in taxonomic composition and abundance of siphonophores were due to the influence of the coastal upwelling and surface ocean currents of the South China Sea,driven by the East Asia monsoonal system.  相似文献   

A comparative study of sea surface wind datasets and their induced circulation characteristics in the North Pacific Ocean     

Wang  Dingqi  Fang  Guohong  Xu  Tengfei  Jiang  Shumin  Teng  Fei  Qiu  Ting  Wei  Zexun  Wang  Yonggang 《Ocean Dynamics》2023,73(2):59-77

Ocean Dynamics - Mainly driven by wind stress, the upper ocean dynamic processes in the North Pacific Ocean serve as important pathways for mass and energy exchanges of the global ocean and thus...  相似文献