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Calculation of wave and current loads on launching offshore jacket 被引量:6
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作者 ZHANG Guang-fa JI Zhuo-shang LI Tie-li LIN Yan 《Journal of Marine Science and Application》 2006年第4期1-7,共7页
It’s very complicated to calculate and analyze the wave and current loads on naval architectures since the sea condition is uncertain and complicated and the determinants vary from different form types and dimensions... It’s very complicated to calculate and analyze the wave and current loads on naval architectures since the sea condition is uncertain and complicated and the determinants vary from different form types and dimensions. For calculating the wave and current loads on upright small-long-size pipe, the Morrison equation is practical and applied. Jacket platform is a kind of offshore space frame structure comprised of lots of poles that are circular cylinders with small diameter and in the oblique status relative to seabed. In this paper, based on Morrison equation, the specific method and procedure calculating the wave and current loads on launching jacket are given and applied on a typical launching jacket. The instance shows that the method and procedure are convenient and make the calculation and analysis in good agreement with actual launching. 展开更多
关键词 LAUNCHING hydrodynamic force morrison equation jacket platform
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Detecting Changes in Precipitation and Temperature Extremes over China Using a Regional Climate Model with Water Table Dynamics Considered 被引量:1
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作者 QIN Pei-Hua XIE Zheng-Hui WANG Ai-Wen 《Atmospheric and Oceanic Science Letters》 CSCD 2014年第2期103-109,共7页
Simulations were conducted with the regional climate model RegCM incorporating water table dynamics from 1 September 1982 to 28 August 2002 to detect precipitation and temperature extremes. Compared with observed r10(... Simulations were conducted with the regional climate model RegCM incorporating water table dynamics from 1 September 1982 to 28 August 2002 to detect precipitation and temperature extremes. Compared with observed r10(number of days with precipitation ≥ 10 mm d–1), RegCM3_Hydro(the regional climate model with water table dynamics considered) simulated rain belts, including those in southern China and the middle and lower reaches of the Yangtze River, and provided data for arid to semi-arid areas such as the Heihe River Basin in northwestern China. RegCM3_Hydro indicated a significant increasing trend of r95p(days with daily precipitation greater than the 95th percentile of daily amounts) for the Yangtze, Yellow, and Pearl River basins, consistent with r95p observations. The Haihe River Basin was also chosen as a specific case to detect the effect of groundwater on extreme precipitation using peaks over threshold(POT)-based generalized Pareto distribution(GPD) with parameters estimated by the L-moment method. Quantile plots showed that all but a few of the plotted points were distributed near diagonal lines and the modeled data fitted well with the samples. Finally, the effects of water table dynamics on temperature extremes were also evaluated. In the Yellow River Basin and Songhuajiang River Basin, the trends of the number of warm days(TX95n) from RegCM3_Hydro matched observed values more closely when water table dynamics were considered, and clearly increasing numbers of warm days from 1983 to 2001 were detected. 展开更多
关键词 climatic extreme GROUNDWATER RUNOFF river basin regional climate
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Identification and Evolution of Groundwater Chemistry in the Ejin Sub-Basin of the Heihe River, Northwest China 被引量:5
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作者 SU Yong-Hong FENG Qi +2 位作者 ZHU Gao-Feng SI Jian-Hua ZHANG Yan-Wu 《Pedosphere》 SCIE CAS CSCD 2007年第3期331-342,共12页
Hydro-chemical characteristics of groundwater and their changes as affected by human activities were studied in the Ejin Sub-Basin of the Inner Mongolia Autonomous Region, China, to understand the groundwater evolutio... Hydro-chemical characteristics of groundwater and their changes as affected by human activities were studied in the Ejin Sub-Basin of the Inner Mongolia Autonomous Region, China, to understand the groundwater evolution, to identify the predominant geochemical processes taking place along the horizontal groundwater flow path, and to characterize anthropogenic factors affecting the groundwater environment based on previous data. The concentrations of major ions and total dissolved solids (TDS) in the groundwater showed a great variation, with 62.5% of the samples being brackish (TDS ≥ 1 000 mg L^-l). The groundwater system showed a gradual hydro-chemical zonation composed of Na^+ -HCO3^-, Na^+ -Mg^2+ -SO4 ^2 -Cl^-, and Na^+ -Cl^-. The relationships among the dissolved species allowed identification of the origin of solutes and the processes that generated the observed water compositions. The dissolution of halite, dolomite, and 2- gypsum explained, in part, the presence of Na^+, K^+, Cl^-, SO^4 , and Ca^2+, but other processes, such as mixing, Na^+ exchange for Ca^2+ and Mg^2+, and calcite precipitation also contributed to the composition of water. Human activity, in particular large-scale water resources development associated with dramatic population growth in the last 50 years, has led to tremendous changes in the groundwater regime, which reflected in surface water runoff change, decline of groundwater table and degeneration of surface water and groundwater quality. Solving these largely anthropogenic problems requires concerted, massive and long-term efforts. 展开更多
关键词 Ejin Sub-Basin groundwater quality Heihe River human impact water resources development
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A Modified Groundwater Module in SWAT for Improved Streamflow Simulation in a Large, Arid Endorheic River Watershed in Northwest China 被引量:6
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作者 JIN Xin HE Chansheng +1 位作者 ZHANG Lanhui ZHANG Baoqing 《Chinese Geographical Science》 SCIE CSCD 2018年第1期47-60,共14页
Interactions between surface water and groundwater are dynamic and complex in large endorheic river watersheds in Northwest China due to the influence of both irrigation practices and the local terrain. These interact... Interactions between surface water and groundwater are dynamic and complex in large endorheic river watersheds in Northwest China due to the influence of both irrigation practices and the local terrain. These interactions interchange numerous times throughout the middle reaches, making streamflow simulation a challenge in endorheic river watersheds. In this study, we modified the linear-reservoir groundwater module in SWAT(Soil and Water Assessment Tools, a widely used hydrological model) with a new nonlinear relationship to better represent groundwater processes; we then applied the original SWAT and modified SWAT to the Heihe River Watershed, the second largest endorheic river watershed in Northwest China, to simulate streamflow. After calibrating both the original SWAT model and the modified SWAT model, we analyzed model performance during two periods: an irrigation period and a non-irrigation period. Our results show that the modified SWAT model with the nonlinear groundwater module performed significantly better during both the irrigation and non-irrigation periods. Moreover, after comparing different runoff components simulated by the two models, the results show that, after the implementation of the new nonlinear groundwater module in SWAT, proportions of runoff components changed-and the groundwater flow had significantly increased, dominating the discharge season. Therefore, SWAT coupled with the non-linear groundwater module represents the complex hydrological process in the study area more realistically. Moreover, the results for various runoff components simulated by the modified SWAT models can be used to describe the hydrological characteristics of lowland areas. This indicates that the modified SWAT model is applicable to simulate complex hydrological process of arid endorheic rivers. 展开更多
关键词 Soil and Water Assessment Tools (SWAT) GROUNDWATER irrigation streamflow Heihe River
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Variation characteristics of aquifer parameters induced by groundwater source heat pump operation under variable flow 被引量:5
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作者 王松庆 张旭 《Journal of Central South University》 SCIE EI CAS 2011年第4期1272-1277,共6页
The variation characteristics of aquifer parameters,induced by groundwater source heat pump(GWSHP) operation under variable flow,were theoretically analyzed through a case study,in which the characteristics of buildin... The variation characteristics of aquifer parameters,induced by groundwater source heat pump(GWSHP) operation under variable flow,were theoretically analyzed through a case study,in which the characteristics of building air conditioning load were considered.The results,compared with the constant flow operation,indicate that the influence on the variations of porosity,hydraulic conductivity and confined water head is decreased by 48%,51% and 71%,respectively,under variable flow operation.The security of variable flow operation is superior to that of constant flow.It is also concluded that the climate region and function of the buildings are primary factors which affect the suitability of variable flow operation in GWSHP. 展开更多
关键词 groundwater source heat pump variation characteristic aquifer parameter variable flow
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Study on water loss of the surface stream affected by iongwali mining
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作者 郭文兵 Syd S. Peng 《Journal of Coal Science & Engineering(China)》 2007年第1期22-27,共6页
In order to study the effect of Iongwall mining on surface stream water, monitoring stations of water flow rate was established. A lot of water flowing data were collected before, during and after Iongwall mining. Bas... In order to study the effect of Iongwall mining on surface stream water, monitoring stations of water flow rate was established. A lot of water flowing data were collected before, during and after Iongwall mining. Based on monitoring data, the effects of Iongwall mining on surface stream water were analyzed. The results demonstrate that Iongwall mining has effects on the surface stream water; and the stream water would be lost and decrease due to Iongwall mining but never go into underground through fractured zone. Also, the mechanism of water loss due to Iongwall mining was presented. The stream water can go into the surface cracks in the intersection of stream and surface cracks, longwall mining subsidence can change the surface stream slope and the downstream water flowing status. The results also show the effects of Iongwall mining on stream water are temporary and about one or two years later, surface stream water can be recovered. 展开更多
关键词 longwall mining surface water STREAM mining under water bodies
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Groundwater Flow Modelling of Galma Basin, Nigeria: Using Finite Element Method
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作者 I.O. Olaniyan J.C. Agunwamba J.O. Ademiluyi 《Journal of Environmental Science and Engineering》 2011年第3期247-252,共6页
The groundwater flow characteristics of the Galma River Basin were simulated numerically by using the finite element method. The two-dimensional partial differential equation governing transient flow in an unconfined ... The groundwater flow characteristics of the Galma River Basin were simulated numerically by using the finite element method. The two-dimensional partial differential equation governing transient flow in an unconfined aquifer was modified to incorporate the effect of precipitation as a measurable source as it affects groundwater flow, such that for a given amount of precipitation over the basin, the flow of groundwater can be predicted at any point in the basin. With appropriate initial and boundary conditions, the modified equation was solved and the solution programmed for computer run. After calibration and verification, the borehole hydraulic data for the basin was used to predict flow due to groundwater hydraulic heads for 20 years. Findings revealed that there is a direct correlation of 0.79 and a strong linear relationship between simulated and observed hydraulic heads, and that data availability and choice of appropriate initial and boundary conditions are significant for good numerical modelling results. The contour plot of the hydraulic heads showed variation of heads from higher values at the upstream to lower values downstream, and groundwater flow follows the natural topography of the land from the upstream end of the basin towards the main streams and Galma River. 展开更多
关键词 Groundwater flow river basin PRECIPITATION finite element hydraulic head.
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Northern Hemisphere Stratospheric Polar Vortex Extremes in February under the Control of Downward Wave Flux in the Lower Stratosphere 被引量:1
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作者 WEI Ke CHEN Wen 《Atmospheric and Oceanic Science Letters》 2012年第3期183-188,共6页
Using ECWMF ERA-40 and Interim reanalysis data, the planetary wave fluxes associated with the February extreme stratospheric polar vortex were studied. Using the three-dimensional Eliassen-Palm (EP) flux as a measure ... Using ECWMF ERA-40 and Interim reanalysis data, the planetary wave fluxes associated with the February extreme stratospheric polar vortex were studied. Using the three-dimensional Eliassen-Palm (EP) flux as a measure of the wave activity propagation, the authors show that the unusual warm years in the Arctic feature an anomalous weak stratosphere-troposphere coupling and weak downward wave flux at the lower stratosphere, especially over the North America and North Atlantic (NANA) region. The extremely cold years are characterized by strong stratosphere-troposphere coupling and strong downward wave flux in this region. The refractive index is used to examine the conception of planetary wave reflection, which shows a large refractive index (low reflection) for the extremely warm years and a small refractive index (high reflection) for the extremely cold years. This study reveals the importance of the downward planetary wave propagation from the stratosphere to the troposphere for explaining the unusual state of the stratospheric polar vortex in February. 展开更多
关键词 stratospheric sudden warming atmospheric dynamics middle atmosphere planetary wave reflection
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Trends in Annual and Seasonal Pan Evaporation in the Lower Yellow River Basin from 1961 to 2010 被引量:7
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作者 JI Xing-Jie WANG Ji-Jun +2 位作者 GU Wan-Long ZHU Ye-Yu LI Feng-Xiu 《Advances in Climate Change Research》 SCIE 2012年第4期195-204,共10页
The annual and seasonal trends in pan evaporation in the lower Yellow River Basin based on quality-controlled data from 10 meteorological stations in 1961-2010 are analyzed. The causes for the changes in annual and se... The annual and seasonal trends in pan evaporation in the lower Yellow River Basin based on quality-controlled data from 10 meteorological stations in 1961-2010 are analyzed. The causes for the changes in annual and seasonal pan evaporation are also discussed. The results suggest that, despite the 1.15~C increasing in annual mean surface air temperature over the past 50 years (0.23°C per decade), the annual pan evaporation has steadily declined by an average rate of-7.65 mm per year. By comparison, this change is greater than those previously reported in China. Significant decreasing trends in annual pan evaporation have been observed at almost all stations. As a whole, seasonal pan evaporation decreased significantly, especially in summer, whereas seasonal temperature increased significantly, except in summer. Thus, the pan evaporation paradox exists in the lower Yellow River Basin. The trend analysis of other meteorological factors indicates significant decrease in sunshine duration and wind speed, but no significant variations in precipitation and relative humidity at annual and seasonal time scales. By examining the relationship between precipitation and pan evaporation, it did not show a concurrent decrease in pan evaporation and increase in precipitation. The partial correlation analysis discovered that the primary cause of decrease in annual and seasonal pan evaporation is the decrease in wind speed. A further examination using a stepwise regression shows that decrease in wind speed and sunshine duration, and increase in mean temperature axe likely to be the main meteorological factors affecting the annual and seasonal pan evaporation in the lower Yellow River Basin over the past 50 years. 展开更多
关键词 lower Yellow River Basin pan evaporation TREND meteorological factors
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Small Excess and the Topology of Open Manifolds with Ricci Curvature Negatively Lower Bounded
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作者 XU Sen-lin HU Zi-sheng 《Chinese Quarterly Journal of Mathematics》 CSCD 北大核心 2007年第1期16-21,共6页
In this paper, we study the relation between the excess of open manifolds and their topology by using the methods of comparison geometry. We prove that a complete open Riemmannian manifold with Ricci curvature negativ... In this paper, we study the relation between the excess of open manifolds and their topology by using the methods of comparison geometry. We prove that a complete open Riemmannian manifold with Ricci curvature negatively lower bounded is of finite topological type provided that the conjugate radius is bounded from below by a positive constant and its Excess is bounded by some function of its conjugate radius, which improves some results in [4]. 展开更多
关键词 open manifolds Ricci curvature conjugate radius critical point Excess function triangle comparison theorems
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An Experimental Study on the Observation Method of Hydrogen Concentration in Fault Gas
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作者 Fan Xuefang Li Zihong +3 位作者 Li Bin Liu Guojun Huang Chunling Wang Xiangyang 《Earthquake Research in China》 2014年第3期335-349,共15页
In order to explore the new technology and methods for seismic underground fluid observation,a test study on measurement of hydrogen concentration in fault gas is carried out at the piedmont fault zone of Zhongtiao Mo... In order to explore the new technology and methods for seismic underground fluid observation,a test study on measurement of hydrogen concentration in fault gas is carried out at the piedmont fault zone of Zhongtiao Mountain. Through the experiment on observation positions,gas collection devices and sampling depths,the paper presents the observation method for fault gas hydrogen concentration by using an online automatic trace hydrogen analyzer. Comparative tests are conducted on the stability and optimum conditions of this type of instrument in the field environment, and the hydrogen concentrations at different measuring points of the same fault are observed. The results show that it is technically feasible to carry out continuous hydrogen concentration on a fault zone. The method proposed in this study could be a useful tool for setting the observation points,choosing a reasonable observation depth and scientific analysis of the observed data. 展开更多
关键词 The piedmont fault zone of Zhongtiao Mountain Fault gas Theconcentration of hydrogen Continuous observation New technique forseismic monitoring
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Climate Change and Water Resources: Strategies and Practices for Improved Water Management in Arid Countries
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作者 B. S. Choudri Mushtaque Ahmed 《Journal of Agricultural Science and Technology(A)》 2012年第3期335-344,共10页
Assessment report of the Intergovernmental Panel on Climate Change (IPCC) highlighted the complex linkages between climate change and water. The likely warmer climate induced by the climate change is set to alter hy... Assessment report of the Intergovernmental Panel on Climate Change (IPCC) highlighted the complex linkages between climate change and water. The likely warmer climate induced by the climate change is set to alter hydrological cycle and the shifting pattern of the rainfall would affect the spatial and temporal distribution of runoff, soil moisture, and surface and groundwater reserves. Therefore, there is an urgent need to assess the impacts of climate change on water and devise adaptation measures including management structures and processes by which one can deal with this challenge. The paper highlights with the global overview of climate change impacts on water in the arid region, supported and substantiated through scientific evidence drawn from IPCC reports and other relevant documents. This paper provides an overview of water resource management challenges including transboundary geopolitical concerns documented across the world and emphasizes the importance of an integrated framework for adaptive policy making. Further, it examines the viable water resource management options for various sectors and regions and showcases some of the international best practices in adaptation and mitigation. The paper also explains the complementary role of traditional knowledge in coping with climate change risks and uncertainties and the need for a balanced view in designing adaptation and mitigation strategies. 展开更多
关键词 Climate change RAINFALL water resource management adaptation.
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Relationship between Hydrogeological Structure and Groundwater Exploitation Capacity in Aquifer of the Basin of Cai Phan Rang River, Ninh Thuan Province, Viet Nam
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作者 Nguyen Minh Khuyen Nguyen Hong Hieu Doan Van Long Le Thanh Tung 《Journal of Environmental Science and Engineering(A)》 2014年第1期32-41,共10页
This article presents the results of dividing the hydrogeological structure zones in aquifer of Cai Phan Rang river basin, Ninh Thuan province, Viet Nam, and the relationship between parameters of hydrogeological stru... This article presents the results of dividing the hydrogeological structure zones in aquifer of Cai Phan Rang river basin, Ninh Thuan province, Viet Nam, and the relationship between parameters of hydrogeological structure zones with water storage capacity of hydrogeological structure. Research results divided hydrogeological structure of Cai Phan Rang River Basin into four zones, including three zones with depression bedrock and one zone with slope bedrock, and the results assessed: (1) specific discharge of exploitation well is proportional to zone area of hydrogeological structure; (2) specific discharge of exploitation well is inversely proportional to slope of bedrock surface, slope of water level in zone and area of drainage surface of hydrogeological structure zone; (3) water level fluctuation in zone is proportional to slope of bedrock surface, slope of water level in zone and inversely proportional to distribution area of zone; (4) total mineralization of water is proportional to bedrock surface slope and water level slope in zone, and inversely proportional to drainage surface area of zone and volume of structural depression. Research results are practical significance in solutions proposal to increase exploitation capacity for various water use purposes. 展开更多
关键词 Hydrogeological structure groundwater exploitation capacity
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Free Transverse Vibration Analysis of an Underwater Launcher Based on Fluid-Structure Interaction
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作者 Qingyong Niu 《Journal of Marine Science and Application》 2014年第2期178-184,共7页
A pneumatic launcher is theoretically investigated to study its natural transverse vibration in water. Considering the mass effect of the sealing cover, the launcher is simplified as a uniform cantilever beam with a t... A pneumatic launcher is theoretically investigated to study its natural transverse vibration in water. Considering the mass effect of the sealing cover, the launcher is simplified as a uniform cantilever beam with a top point mass. By introducing the boundary and continuity conditions into the motion equation, the natural frequency equation and the mode shape function are derived. An iterative calculation method for added mass is also presented using the velocity potential function to account for the mass effect of the fluid on the launcher. The first 2 order natural frequencies and mode shapes are discussed in external flow fields and both external and internal flow fields. The results show good agreement with both natural frequencies and mode shapes between the theoretical analysis and the FEM studies. Also, the added mass is found to decrease with the increase of the mode shape orders of the launcher. And because of the larger added mass in both the external and internal flow fields than that in only the external flow field, the corresponding natural frequencies of the former are relatively smaller. 展开更多
关键词 underwater launcher free transverse vibration naturalfrequency mode shape added mass fluid-structure interaction
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The Extent of Land Use Impact on Water Regime in the Vseminka Catchment
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作者 Pavel Kovar Darina Vassova 《Journal of Environmental Science and Engineering(B)》 2012年第2期228-237,共10页
The paper deals with the impact of land use changes on water regime. An assessment was carried out in order to determine the extent to which the main components of the water balance on the experimental catchment Vsemi... The paper deals with the impact of land use changes on water regime. An assessment was carried out in order to determine the extent to which the main components of the water balance on the experimental catchment Vseminka have been influenced by land use changes (region Vsetinske Hills, the Czech Republic). For this reason, the water balance model WBCM-5 was implemented for the period of 30 years in a daily step, with particular focus on the simulation of the components of direct runoff and of subsurface water recharge. In the selected years of the period 1980-2009, major changes were made in land use and significant fluctuation of rainfall-runoff regimes were observed (e.g. dry year 1992, flood year 1997 and normal year 2009). After WBCM-5 parameter calibration it was observed that some water balance components can change in relation to substantial land use changes, even up to dozens of percent in a balance-consideration, i.e. in daily, monthly and yearly or decadal values, specifically as far as the components of interception and also of direct runoff and of subsurface water recharge are concerned. However, a different situation appeared during the investigation of significant short-term rainfall-runoff processes. There were about seven real flood events during the same period on the same catchment which were analysed using the KINFIL-2 model (time step 0.5 hr). Land use change, positive or negative scenarios, were also analysed during this period. As opposed to long-term water balance analyses, only a 10% difference in the hydrograph peak and volume was observed. In summary, the authors have shown that it is always important to distinguish a possible land use change impact on either long-term balance or short-term runoff. Otherwise, as often found in over simplified commentaries on flood events in the mass media, the actual impact of land use changes on water regime may be misunderstood. 展开更多
关键词 Land use change water balance rainfall-runoff event hydrological model.
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数字
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《侨园》 2013年第11期5-5,共1页
878亿美元39.96万人《2012年度中国对外直接投资统计公报》显示,去年中国对外直接投资创下流量878亿美元的历史新高,同比增长17.6%,首次成为世界三大对外投资国之一。据统计,截至2012年底,中国对外直接投资累计净额(存量)达5319.4亿美元... 878亿美元39.96万人《2012年度中国对外直接投资统计公报》显示,去年中国对外直接投资创下流量878亿美元的历史新高,同比增长17.6%,首次成为世界三大对外投资国之一。据统计,截至2012年底,中国对外直接投资累计净额(存量)达5319.4亿美元,位居全球第十三位。但由于中国对外直接投资起步较晚,与发达国家相比仍有较大差距,仅相当于美国对外投资存量的10.2%。 展开更多
关键词 对外直接投资 对外投资 统计公报 中国电视 下流量 发达国家 美元 留学生 存量 试验区
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Effects of Bahia Grass Cover and Mulch on Runoff and Sediment Yield of Sloping Red Soil in Southern China 被引量:14
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作者 LI Xin-Hu ZHANG Zhan-Yu +2 位作者 YANG Jie ZHANG Guo-Hua WANG Bin 《Pedosphere》 SCIE CAS CSCD 2011年第2期238-243,共6页
Rainfall,runoff (surface runoff,interflow and groundwater runoff) and soil loss from 5 m × 15 m plots were recorded for 5 years (2001-2005) in an experiment with three treatments (cover,mulch and bare ground) on ... Rainfall,runoff (surface runoff,interflow and groundwater runoff) and soil loss from 5 m × 15 m plots were recorded for 5 years (2001-2005) in an experiment with three treatments (cover,mulch and bare ground) on sloping red soil in southern China.Surface runoff and erosion from the Bahia grass (Paspalum notatum Flugge) cover plot (A) and mulch plot (B) during the 5 years were low,despite the occurrence of potentially erosive rains.In contrast,the bare plot (C) had both the highest surface runoff coefficient and the highest sediment yield.There were significant differences in interflow and surface runoff and no significant difference in groundwater runoff among plots.The runoff coefficients and duration of interflow and groundwater runoff were in the order plot B > plot A > plot C.Effects of Bahia grass cover were excellent,indicating that the use of Bahia grass cover can be a simple and feasible practice for soil and water conservation on sloping red soil in the region. 展开更多
关键词 groundwater runoff INTERFLOW LYSIMETER soil properties surface runoff
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Experimental investigation of the generation of large-amplitude internal solitary wave and its interaction with a submerged slender body 被引量:23
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作者 WEI Gang DU Hui +4 位作者 XU XiaoHui ZHANG YuanMing QU ZiYun HU TianQun YOU YunXiang 《Science China(Physics,Mechanics & Astronomy)》 SCIE EI CAS 2014年第2期301-310,共10页
A principle of generating the nonlinear large-amplitude internal wave in a stratified fluid tank with large cross-section is pro- posed according to the 'jalousie' control mode. A new wave-maker based on the princip... A principle of generating the nonlinear large-amplitude internal wave in a stratified fluid tank with large cross-section is pro- posed according to the 'jalousie' control mode. A new wave-maker based on the principle was manufactured and the experi- ments on the generation and evolution of internal solitary wave were conducted. Both the validity of the new device and ap- plicability range of the KdV-type internal soliton theory were tested. Furthermore, a measurement technique of hydrodynamic load of internal waves was developed. By means of accurately measuring slight variations of internal wave forces exerted on a slender body in the tank, their interaction characteristics were determined. It is shown that through establishing the similarity between the model scale in the stratified fluid tank and the full scale in the numerical simulation the obtained measurement re- suits of internal wave forces are confirmed to be correct. 展开更多
关键词 internal solitary wave wave-maker stratified fluid slender body INTERACTION
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On the Pressure Drop and the Velocity Distribution in the Cylindrical Vortex Chamber with Two Inlet Pipes for the Control of Vortex Flow 被引量:3
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作者 Akira OGAWA Tutomu OONO +2 位作者 Hayato OKABE Noriaki AKIBA Taketo OOYAGI 《Journal of Thermal Science》 SCIE EI CAS CSCD 2005年第2期162-171,共10页
Vortex flow is applied to a cyclone dust collector, a vortex combustion chamber, and a vortex diode for vortex control. In order to apply the vortex flow to the industries, it is necessary to keep the stable flow cond... Vortex flow is applied to a cyclone dust collector, a vortex combustion chamber, and a vortex diode for vortex control. In order to apply the vortex flow to the industries, it is necessary to keep the stable flow condition and to estimate the response time of the transient flow process and also the intensity of the vortex flow. For control vortex flow, two types of vortex chamber with two inlet pipes were designed. One of them is to promote the vortex flow named as Co-Rotating Flow System and another one is to hinder the vortex flow named as Counter-Rotating Flow System. The pressure drops and the velocity distributions were measured for these vortex chambers. The estimation of the tangential velocity by the application of the angular momentum flux is compared with the measured velocity by a cylindrical Pitot-tube. The characteristics of the total pressure drop could be explained by introducing the circulation. 展开更多
关键词 vortex chamber tangential velocity total and local pressure drops angular momentum flux circulation.
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The discovery of surface runoff in the megadunes of Badain Jaran Desert,China,and its significance 被引量:4
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作者 ZHAO JingBo MA YanDong +3 位作者 LUO XiaoQing YUE DaPeng SHAO TianJie DONG ZhiBao 《Science China Earth Sciences》 SCIE EI CAS CSCD 2017年第4期707-719,共13页
The Badain Jaran Desert exhibits the greatest difference in altitude of all of the world's deserts.On the slopes of megadunes in the desert,there are physical and chemical deposits produced by surface runoff.In ad... The Badain Jaran Desert exhibits the greatest difference in altitude of all of the world's deserts.On the slopes of megadunes in the desert,there are physical and chemical deposits produced by surface runoff.In addition,we have observed rarely-seen infiltration-excess surface runoff in the megadune depressions as well as spring streams at the base of megadunes.We used electron microscopy,energy spectrum analysis,infiltration experiments,moisture content determinations and grain-size analysis to study the mineral and chemical composition of the runoff precipitates,and grain-size of the deposits associated with the runoff,together with the hydrological balance in the megadune area,and the atmospheric precipitation mechanism responsible for groundwater recharge and for supplying water to lakes.The observations of shallow runoff and infiltration-excess surface runoff indicate the occurrence of strong and effective precipitation in summer,which would provide an important source for groundwater recharge.Several lines of evidence,such as the physical and chemical deposits resulting from shallow subsurface runoff,spring streams,infiltration-excess runoff,and gravity capillary water with a moisture content of 3-6%,demonstrate that precipitation reaches the base of the megadunes through infiltration and subsequently becomes groundwater.The chemical deposits,such as newly-formed calcite and gypsum,and gray-black physical deposits,as well as different stages in the development of fan-shaped landforms resulting from shallow subsurface runoff,indicate that groundwater recharge in the area is the result of long-term precipitation,rather than intermittent individual major rainfall events.Fine sand layers with a low infiltration capacity lead to subsurface runoff emerging at the ground surface.Five factors play an important role in maintaining a positive water balance and in replenishing groundwater via rainfall:effective rainfall as a water source,the high infiltration capacity of the sands enabling rainfall to rapidly become capillary water in the dunes,low evapotranspiration rates due to the sparse vegetation,the fact that the depth of the sand layer influenced by evaporation is shallow enough to maximize the deep infiltration of rainfall,and rapidly-moving gravity capillary water in the sandy dunes.These five factors together constitute a mechanism for groundwater recharge from rainfall,and explain the origin of the groundwater and lakes in the area.Our findings represent a significant advance in research on the hydrological cycle,including groundwater recharge conditions and recharge mechanisms,in this desert region. 展开更多
关键词 Bedmap-2 Seafloor topography Iceberg grounding Antarctica
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