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船舶气囊下水工艺实践与发展前景 被引量:10
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作者 涂少波 《中国造船》 EI CSCD 北大核心 1997年第3期88-92,共5页
本文叙述船舶气囊下水新工艺在我国内河中、小型船厂近年来的实践,提出和总结气囊下水工艺有关计算方法和注意事项。鉴于气囊下水新工艺有其独特的优越性,并随着气囊制造质量和下水工艺不断完善提高,气囊下水新工艺必会有较好的发展... 本文叙述船舶气囊下水新工艺在我国内河中、小型船厂近年来的实践,提出和总结气囊下水工艺有关计算方法和注意事项。鉴于气囊下水新工艺有其独特的优越性,并随着气囊制造质量和下水工艺不断完善提高,气囊下水新工艺必会有较好的发展前景,下水船舶重量期望可提高到2000t。 展开更多
关键词 船舶 下水工艺 气囊 下水力学 计算
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The role of potential soil cavity on ground subsidence and collapse in coal mining area 被引量:6
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作者 OUYANG Zhen-hua 《Journal of Coal Science & Engineering(China)》 2010年第3期240-245,共6页
Based on five basic assumptions, of the ground subsidence and collapse was using theoretical analysis method, the nature revealed from the mechanics point. Divided into four phases as groundwater level descent, soil c... Based on five basic assumptions, of the ground subsidence and collapse was using theoretical analysis method, the nature revealed from the mechanics point. Divided into four phases as groundwater level descent, soil cavity formation, soil cavity expansion, and ground collapse emersion, the whole process of ground subsidence and collapse was analyzed in detail. The study shows that ground subsidence and collapse is the macro- scopic performance and inevitable result of the soil cavity expansion and development, and the dynamic mechanics is the spalling force induced by the groundwater falling. The activities of underground water play a very important role in the process from the formation of soil cavity to the production of ground subsidence. 展开更多
关键词 potential soil cavity ground subsidence and collapse GROUNDWATER spalling force
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Using CFD Software to Calculate Hydrodynamic Coefficients 被引量:9
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作者 张赫 徐玉如 蔡昊鹏 《Journal of Marine Science and Application》 2010年第2期149-155,共7页
Applications of computational fluid dynamic(CFD) to the maritime industry continue to grow with the increasing development of computers.Numerical approaches have evolved to a level of accuracy which allows them to be ... Applications of computational fluid dynamic(CFD) to the maritime industry continue to grow with the increasing development of computers.Numerical approaches have evolved to a level of accuracy which allows them to be applied for hydrodynamic computations in industry areas.Hydrodynamic tests,especially planar-motion-mechanism(PMM) tests are simulated by CFD software-FLUENT,and all of the corresponding hydrodynamic coefficients are obtained,which satisfy the need of establishing the simulation system to evaluate maneuverability of vehicles during the autonomous underwater vehicle scheme design stage.The established simulation system performed well in tests. 展开更多
关键词 FLUENT planar-motion-mechanism (PMM) hydrodynamic coefficients motion simulation
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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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Mechanical properties of underwater friction stir welded 2219 aluminum alloy 被引量:8
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作者 刘会杰 张会杰 +1 位作者 黄永宪 于雷 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2010年第8期1387-1391,共5页
Underwater friction stir welding of 2219 aluminum alloy was carried out in order to further improve the joint performances by varying welding temperature history.The results indicated that the tensile strength of the ... Underwater friction stir welding of 2219 aluminum alloy was carried out in order to further improve the joint performances by varying welding temperature history.The results indicated that the tensile strength of the joint can be improved from 324 MPa by external water cooling action in normal to 341 MPa.However,the plasticity of the joint is deteriorated.The underwater joint tends to fracture at the interface between the weld nugget zone and the thermal mechanically affected zone on the advancing side during tensile test,which is significantly different from the normal joint. 展开更多
关键词 aluminum alloy underwater friction stir welding mechanical property
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Non-Uniform Sediment Transport Downstream from Reservoir 被引量:2
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作者 李义天 陈飞 《Transactions of Tianjin University》 EI CAS 2008年第4期263-270,共8页
The transport characters of non-uniform sediment before and after the reservoir operation are compared and analyzed. Field data from the Three Gorges Reservoir (TGR), Danjiangkou, and Sanmenxia reservoir indicate that... The transport characters of non-uniform sediment before and after the reservoir operation are compared and analyzed. Field data from the Three Gorges Reservoir (TGR), Danjiangkou, and Sanmenxia reservoir indicate that the transport character of coarse particle is various in different reaches. Before the reservoir operation, the dramatic decrease of the hydraulic condition in some reaches is the main reason to cause the coarse particle deposited. After the reservoir operation, almost all grain sized sediment may be eroded, when the reach is eroded seriously. However, the transport character of the coarse particle will be consistent with what it was before, when the reach is not eroded seriously. The deposition amount will be less than its pre-dam value, and it will tend to decrease with the time going on. Erosion of fine particle results from its unsaturation. Longdistance erosion downstream from reservoir is caused by shortage of the supply from riverbed, especially the shortage of fine particle. 展开更多
关键词 downstream from reservoir grain sized sediment hydraulic condition
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Dynamics Modeling and Simulation of Autonomous Underwater Vehicles with Appendages 被引量:3
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作者 Yumin Su Jinxin Zhao Jian Cao Guocheng Zhang 《Journal of Marine Science and Application》 2013年第1期45-51,共7页
To provide a simulation system platform for designing and debugging a small autonomous underwater vehicle's (AUV) motion controller, a six-degree of freedom (6-DOF) dynamic model for AUV controlled by thruster an... To provide a simulation system platform for designing and debugging a small autonomous underwater vehicle's (AUV) motion controller, a six-degree of freedom (6-DOF) dynamic model for AUV controlled by thruster and fins with appendages is examined. Based on the dynamic model, a simulation system for the AUV's motion is established. The different kinds of typical motions are simulated to analyze the motion performance and the maneuverability of the AUV. In order to evaluate the influences of appendages on the motion performance of the AUV, simulations of the AUV with and without appendages are performed and compared. The results demonstrate the AUV has good maneuverability with and without appendages. 展开更多
关键词 autonomous underwater vehicle (AUV) motion performance dynamics modeling appendages simulation system
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Numerical computation and analysis of unsteady viscous flow around autonomous underwater vehicle with propellers based on sliding mesh 被引量:4
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作者 高富东 潘存云 韩艳艳 《Journal of Central South University》 SCIE EI CAS 2012年第4期944-952,共9页
The flexible transmission shaft and wheel propeller are combined as the kinetic source equipment, which realizes the nmlti-motion modes of the autonomous underwater vehicle (AUV) such as vectored thruster and wheele... The flexible transmission shaft and wheel propeller are combined as the kinetic source equipment, which realizes the nmlti-motion modes of the autonomous underwater vehicle (AUV) such as vectored thruster and wheeled movement. In order to study the interactional principle between the hull and the wheel propellers while the AUV navigating in water, the computational fluid dynamics (CFD) method is used to simulate numerically the unsteady viscous flow around AUV with propellers by using the Reynolds-averaged Navier-Stokes (RANS) equations, shear-stress transport (SST) k-w model and pressure with splitting of operators (PISO) algorithm based on sliding mesh. The hydrodynamic parameters of AUV with propellers such as resistance, pressure and velocity are got, which reflect well the real ambient flow field of AUV with propellers. Then, the semi-implicit method for pressure-linked equations (SIMPLE) algorithm is used to compute the steady viscous flow field of AUV hull and propellers, respectively. The computational results agree well with the experimental data, which shows that the numerical method has good accuracy in the prediction of hydrodynamic performance. The interaction between AUV hull and wheel propellers is predicted qualitatively and quantitatively by comparing the hydrodynamic parameters such as resistance, pressure and velocity with those from integral computation and partial computation of the viscous flow around AUV with propellers, which provides an effective reference to the shady on noise and vibration of AUV hull and propellers in real environment. It also provides technical support for the design of new AUVs. 展开更多
关键词 computational fluid dynamics sliding mesh wheel propeller autonomous underwater vehicle viscous flow field
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A Potential Flow Based Flight Simulator for an Underwater Glider 被引量:3
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作者 Surasak Phoemsapthawee Marc Le Boulluec +1 位作者 Jean-Marc Laurens Fran ois Deniset 《Journal of Marine Science and Application》 2013年第1期112-121,共10页
Underwater gliders are recent innovative types of autonomous underwater vehicles (AUVs) used in ocean exploration and observation. They adjust their buoyancy to dive and to return to the ocean surface. During the ch... Underwater gliders are recent innovative types of autonomous underwater vehicles (AUVs) used in ocean exploration and observation. They adjust their buoyancy to dive and to return to the ocean surface. During the change of altitude, they use the hydrodynamic forces developed by their wings to move forward. Their flights are controlled by changing the position of their centers of gravity and their buoyancy to adjust their trim and heel angles. For better flight control, the understanding of the hydrodynamic behavior and the flight mechanics of the underwater glider is necessary. A 6-DOF motion simulator is coupled with an unsteady potential flow model for this purpose. In some specific cases, the numerical study demonstrates that an inappropriate stabilizer dimension can cause counter-steering behavior. The simulator can be used to improve the automatic flight control. It can also be used for the hydrodynamic design optimization of the devices. 展开更多
关键词 underwater glider potential flow Newton-Euler equation autonomous underwater vehicles (AUVs) flight simulator
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Numerical computation and analysis of high-speed autonomous underwater vehicle (AUV) moving in head sea based on dynamic mesh 被引量:2
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作者 高富东 潘存云 +1 位作者 徐小军 韩艳艳 《Journal of Central South University》 SCIE EI CAS 2012年第11期3084-3093,共10页
Autonomous underwater vehicles (AUVs) navigating on the sea surface are usually required to complete the communication tasks in complex sea conditions. The movement forms and flow field characteristics of a multi-mo... Autonomous underwater vehicles (AUVs) navigating on the sea surface are usually required to complete the communication tasks in complex sea conditions. The movement forms and flow field characteristics of a multi-moving state AUV navigating in head sea at high speed were studied. The mathematical model on longitudinal motion of the high-speed AUV in head sea was established with considering the hydrodynamic lift based on strip theory, which was solved to get the heave and pitch of the AUV by Gaussian elimination method. Based on this, computational fluid dynamics (CFD) method was used to establish the mathematical model of the unsteady viscous flow around the AUV with considering free surface effort by using the Reynolds-averaged Navier-Stokes (RANS) equations, shear-stress transport (SST) k-w model and volume of fluid (VOF) model. The three-dimensional numerical wave in the computational field was realized through defining the unsteady inlet boundary condition. The motion forms of the AUV navigating in head sea at high speed were carried out by the program source code of user-defined function (UDF) based on dynamic mesh. The hydrodynamic parameters of the AUV such as drag, lift, pitch torque, velocity, pressure and wave profile were got, which reflect well the real ambient flow field of the AUV navigating in head sea at high speed. The computational wave profile agrees well with the experimental phenomenon of a wave-piercing surface vehicle. The force law of the AUV under the impacts of waves was analyzed qualitatively and quantitatively, which provides an effective theoretical guidance and technical support for the dynamics research and shape design of the AUV in real complex environnaent. 展开更多
关键词 computational fluid dynamics dynamic mesh autonomous underwater vehicle (AUV) MOTION head sea viscous flowfield
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Petroleum Pollution of Groundwater in Zibo and Its Prevention Measures 被引量:1
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作者 徐建芳 武强 李铎 《Journal of China University of Mining and Technology》 2003年第1期24-28,共5页
The source of ground water supply in Dawu is an extremely huge one in Shandong province. Now it is faced with serious pollution of petroleum in Hougao area. Aiming at this problem, the petroleum pollution in aeration ... The source of ground water supply in Dawu is an extremely huge one in Shandong province. Now it is faced with serious pollution of petroleum in Hougao area. Aiming at this problem, the petroleum pollution in aeration zone and in groundwater was analyzed. The result shows that the contaminant of groundwater comes from the leaching of petroleum in the soil horizon of aeration zone through precipitation, and the quick flow of groundwater makes the convection dominate themigration of contaminant. So movement of groundwater controls the distribution of petroleum contaminant, which is consistent with the direction of ground flow. Building a groundwater closure zone in Hougao is an effective method to stop the contaminated groundwater flowing toward the water supply source of Dawu. The petroleum contaminant can be effectively reduced through using the aeration, biological and oxidation technologies. 展开更多
关键词 Groundwater source Dawu area Petroleum pollution Groundwater closure zone aeration biological and oxidation technology
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An Analytic Solution to Well-water Level Changes under Barometric Pressure
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作者 Liu Chunping Deng Liang +2 位作者 Liao Xin Wan Fei Shi Yun 《Earthquake Research in China》 2011年第2期240-249,共10页
Under barometric pressure, groundwater flow in well-aquifer systems is a kind of hydromechanical coupling problem. Applying the flux boundary conditions on borehole wall and water pressure equilibrium conditions insid... Under barometric pressure, groundwater flow in well-aquifer systems is a kind of hydromechanical coupling problem. Applying the flux boundary conditions on borehole wall and water pressure equilibrium conditions inside and outside the borehole wall under barometric pressure (BP), an analytic solution to well-water level changes has been proposed in this paper. The formulation shows that the BP coefficients increase with time and tend to BP constant. The Change of BP coefficients over time depends only on the ratio of transmissivity (T) to the well radius squared ( r2, ) , and has nothing to do with the change in BP. The BP constant only relates to aquifer loading efficiency (B), and has nothing to do with the aquifer transmissivity and well radius. The BP coefficients' change over time in the analytic formulation is consistent with the analysis of measured data from the Nanxi wells. Based on the BP coefficient changes over time, a parameter estimation method is suggested and discussed in its application to the estimation of the aquifer BP constant (or B) and transmissivity by using the Nanxi well data. 展开更多
关键词 Well-water level Barometric pressure Analytic solution PARAMETERESTIMATION Barometric pressure coefficient
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An Assessment of the Groundwater Potential of Bayero University Kano Permanent Site Using Induced Polarization and Self-potential Methods
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作者 Shehu Sani Jamaluddeen Abdulrahim Ali Bunawa Muhammad Saleh 《Journal of Earth Science and Engineering》 2014年第10期587-596,共10页
This paper centers on the investigation of the subsurface condition of Bayero University Kano Permanent Site with the aim of understanding the lithology and also mapping out the groundwater patterns within the area. T... This paper centers on the investigation of the subsurface condition of Bayero University Kano Permanent Site with the aim of understanding the lithology and also mapping out the groundwater patterns within the area. To achieve this, time domain IP (induced polarization) and SP (self-potential) methods were adopted using VES (vertical electrical sounding) technique with 49 stations sounded. The result of the interpreted and analyzed measured data shows that the area is underlain by two to five subsurface layers. These layers are top soil, laterite, weathered basement complex rocks, fractured basement complex rocks and fresh basement complex rocks. The aquiferous zone of the study area occurs in the weathered and fractured basements and its thickness ranges from 1.44 m to 70.157 m while the overburden thickness lies between 1.6 m and 72.104 m. SP values were plotted against depths of investigation in order to identify areas with greater depth of flow in the study area. From the analysis of the overburden thickness, aquifer thickness and SP values, the most favorable regions for groundwater exploitation were found around VES 6, 11, 13, 19, 26, 38, 44 and 48. The investigation also provides information about the subsurface condition with regards to engineering construction and safe place for refuse dumping in order to avoid groundwater contamination. 展开更多
关键词 SUBSURFACE induced polarization self-potential.
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An Approximate Analytical Solution for Grout Transport Modeling: A Case Study in Luling Mining, China 被引量:1
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作者 钱家忠 葛晓光 周念清 《Journal of Shanghai Jiaotong university(Science)》 EI 2008年第5期585-588,共4页
This case study describes the effects of a grouting process developed to decrease groundwater flow exiting from a ruptured mine ventilation shaft lining in Luling coal mine at Huaibei, China. The primary purpose of gr... This case study describes the effects of a grouting process developed to decrease groundwater flow exiting from a ruptured mine ventilation shaft lining in Luling coal mine at Huaibei, China. The primary purpose of grouting at this site is to prevent groundwater flow into the mine from adjacent aquifers. The study supports a transport perspective to describe the miscible grout movement, and provides an approximate analytical method to determine grout concentration based on Wilson and Miller's (1978) model. This study shows that the breakthrough curves (BTCs) established from the Wilson and Miller's model match the experimental BTCs obtained from test grouting performed at the site, and Rd a retardation factor of 1.1 is determined. The retardation factor and the BTC ave subsequently used to guide the actual production grouting. The monitored result shows that the groundwater inflow at the disrupted ventilation well has been reduced by 47% after drilling and grouting just one borehole. The discharge rate was measured at no more than 4 m^3/h after completion of four injection boreholes, which is about 13% of the 30 m^3/h before grouting. 展开更多
关键词 GROUTING hydrodynamic dispersion mine shaft lining
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Use of the Jiaolong manned submersible for accurate mapping of deep-sea topography and geomorphology 被引量:2
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作者 Tongwei ZHANG Jialing TANG +2 位作者 Zhengguang LI Yubin ZHOU Xiangxin WANG 《Science China Earth Sciences》 SCIE EI CAS CSCD 2018年第8期1148-1156,共9页
High-resolution bathymetric side-scan sonar(BSSS) performs the functions of traditional side-scan sonar, while also providing a depth-sounding function that allows simultaneous measurement of seafloor topography and g... High-resolution bathymetric side-scan sonar(BSSS) performs the functions of traditional side-scan sonar, while also providing a depth-sounding function that allows simultaneous measurement of seafloor topography and geomorphology. Submarine microtopography and microgeomorphology detection ability and advanced underwater acoustic digital communication are important technical capabilities of the Jiaolong manned submersible. High resolution BSSS achieved accurate detection of seafloor topography and geomorphology at a depth of 7000 m, and successful mapping of local microtopography and microgeomorphology in the Mariana Trench. 展开更多
关键词 MICROTOPOGRAPHY Microgeomorphology Manned submersible Deep sea High-resolution bathymetric side scan sonar Jiaolong
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