The control value of the deflection of the embedded cylindrical structure, which is the maximum deflection allowed for stability of the cylinder, is a vital quantity of stability calculation. The deflection and the so...The control value of the deflection of the embedded cylindrical structure, which is the maximum deflection allowed for stability of the cylinder, is a vital quantity of stability calculation. The deflection and the soil pressure on the embedded cylinder were investigated by model experiment. When the inclined angle of cylinder is less than or equal to 0.25°, the effective anti-overturning ratio increases gradually and reaches the maximum. When the inclined angle of cylinder is more than 0.25°, the effective anti-overturning ratio decreases gradually. The control value of instability of the cylindrical structure approximates 0.2°. and the bearing stress at the back edge of the cylinder is equal to zero.展开更多
Detachment size determination with an acoustic method has been carried out for two interacting bubble plumes formed at neighboring needles in quiescent water. Two sets of needle pairs, one with 1.5mm and 0.8mm inner d...Detachment size determination with an acoustic method has been carried out for two interacting bubble plumes formed at neighboring needles in quiescent water. Two sets of needle pairs, one with 1.5mm and 0.8mm inner diameters and the other with the equal 1.5mm inner diameters, were separately used as the bubble pair injectors in the experiments. Consequently, four typical patterns of bubble plumes interaction could be observed in the two cases of needle pair matches. Through measuring the pressure pulses radiated by the bubble pairs immediately after their 'pinching-off ' and by making use of a sophisticated relation between oscillation frequency of volume mode and radius of gas bubble, the detachment size of the bubble plumes have been determined from the amplitude/frequency spectrum of the sound pressure pulses. The experimental results demonstrate that the acoustical method is valid in both of the interacting and non-interacting circumstances in bubble field and the bubble size measurements by this acoustical method agree well with the measurements from photographic analysis. Finally, a comparison has been made on the strong and weak points of the acoustical method with the other size determination methods.展开更多
The multipoint steam injection string of the horizontal well is a commonly used downhole component for high efficiency steam injection of the thermal recovery horizontal well. A reasonable layout of the valves to ensu...The multipoint steam injection string of the horizontal well is a commonly used downhole component for high efficiency steam injection of the thermal recovery horizontal well. A reasonable layout of the valves to ensure an even steam output of each point is still not well designed. At present, a general design method which is urgently necessary isn＇ t applied by each factory. According to the balance relationship of the momentum, the energy and the mass of the fluid flowing in the string, the pressure distribution equation of the fluid flowing in the multipoint steam injection string is built. On the basis of this equation, the design calculation method of the multipoint steam injection string is come up with. A specific example is given in the paper. Study shows that, with the equation built in this paper, the string can be designed with each axial valve having the same output, so that the technical demand of an even steam injection of the horizontal well section can be met.展开更多
The atmospheric reanalysis datasets have been widely used to understand the variability of atmospheric water va- por on various temporal and spatial scales for climate change research. The difference among a variety o...The atmospheric reanalysis datasets have been widely used to understand the variability of atmospheric water va- por on various temporal and spatial scales for climate change research. The difference among a variety of reanalysis datasets, however, causes the uncertainty of corresponding results. In this study, the climatology of atmospheric column-integrated wa- ter vapor for the period from 2000 to 2012 was compared among three latest third-generation atmospheric reanalyses including European Centre for Medium-range Weather Forecasts Interim Re-Analysis （ERA-Interim）, Modem-Era Retrospective Analy- sis for Research and Applications （MERRA）, and Climate Forecast System Reanalysis （CFSR）, while possible explanation on the difference between them was given. The results show that there are significant differences among three datasets in the mul- ti-year global distribution, variation of interannual cycle, long-term trend and so on, though high similarity for principal mode describing the variability of water vapor. Over oceans, the characteristics of long-term CWV variability are similar, whereas the main discrepancy among three datasets is located around the equatorial regions of the Intertropical Convergence Zone, the South Pacific Convergence Zone and warm cloud area, which is related with the difference between reanalysis models for the scheme of convective parameterization, the treatment of warm clouds, and the assimilation of satellite-based observations. Moreover, these CWV products are fairly consistent with observations （satellite-based retrievals） for oceans. On the other hand there are systematic underestimations about 2.5 kg/m2 over lands for all three CWV datasets, compared with radiosonde ob- servations. The difference between models to solve land-atmosphere interaction in complex environment, as well as the pauci- ty in radiosonde observations, leads to significant water vapor gaps in the Amazon Basin of South America, central parts of Africa and some mountainous regions. These results would help better understand the climatology difference among various reanalysis datasets better, and more properly choose water vapor datasets for different research requirements.展开更多
基金SUPPORTED BY THE 9TH NATIONAL FIVE-YEAR PROGRAM OF CHINA( NO. 96-415-03-01).
文摘The control value of the deflection of the embedded cylindrical structure, which is the maximum deflection allowed for stability of the cylinder, is a vital quantity of stability calculation. The deflection and the soil pressure on the embedded cylinder were investigated by model experiment. When the inclined angle of cylinder is less than or equal to 0.25°, the effective anti-overturning ratio increases gradually and reaches the maximum. When the inclined angle of cylinder is more than 0.25°, the effective anti-overturning ratio decreases gradually. The control value of instability of the cylindrical structure approximates 0.2°. and the bearing stress at the back edge of the cylinder is equal to zero.
基金Supported by the Post-Doctorate Science Foundation.
文摘Detachment size determination with an acoustic method has been carried out for two interacting bubble plumes formed at neighboring needles in quiescent water. Two sets of needle pairs, one with 1.5mm and 0.8mm inner diameters and the other with the equal 1.5mm inner diameters, were separately used as the bubble pair injectors in the experiments. Consequently, four typical patterns of bubble plumes interaction could be observed in the two cases of needle pair matches. Through measuring the pressure pulses radiated by the bubble pairs immediately after their 'pinching-off ' and by making use of a sophisticated relation between oscillation frequency of volume mode and radius of gas bubble, the detachment size of the bubble plumes have been determined from the amplitude/frequency spectrum of the sound pressure pulses. The experimental results demonstrate that the acoustical method is valid in both of the interacting and non-interacting circumstances in bubble field and the bubble size measurements by this acoustical method agree well with the measurements from photographic analysis. Finally, a comparison has been made on the strong and weak points of the acoustical method with the other size determination methods.
文摘The multipoint steam injection string of the horizontal well is a commonly used downhole component for high efficiency steam injection of the thermal recovery horizontal well. A reasonable layout of the valves to ensure an even steam output of each point is still not well designed. At present, a general design method which is urgently necessary isn＇ t applied by each factory. According to the balance relationship of the momentum, the energy and the mass of the fluid flowing in the string, the pressure distribution equation of the fluid flowing in the multipoint steam injection string is built. On the basis of this equation, the design calculation method of the multipoint steam injection string is come up with. A specific example is given in the paper. Study shows that, with the equation built in this paper, the string can be designed with each axial valve having the same output, so that the technical demand of an even steam injection of the horizontal well section can be met.
基金supported by the National Natural Science Foundation of China(Grant Nos.9133721341230419+5 种基金4137503041375148 and 41205126)the Special Funds for Public Welfare of China(Grant No.GYHY201306077)the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDA05100303)the Knowledge Innovation Program of the Chinese Academy of Sciences(Grant No.KZCX2-EW-QN507)sponsored by the Jiangsu Provincial 2011 Program(Collaborative Innovation Center of Climate Change)
文摘The atmospheric reanalysis datasets have been widely used to understand the variability of atmospheric water va- por on various temporal and spatial scales for climate change research. The difference among a variety of reanalysis datasets, however, causes the uncertainty of corresponding results. In this study, the climatology of atmospheric column-integrated wa- ter vapor for the period from 2000 to 2012 was compared among three latest third-generation atmospheric reanalyses including European Centre for Medium-range Weather Forecasts Interim Re-Analysis （ERA-Interim）, Modem-Era Retrospective Analy- sis for Research and Applications （MERRA）, and Climate Forecast System Reanalysis （CFSR）, while possible explanation on the difference between them was given. The results show that there are significant differences among three datasets in the mul- ti-year global distribution, variation of interannual cycle, long-term trend and so on, though high similarity for principal mode describing the variability of water vapor. Over oceans, the characteristics of long-term CWV variability are similar, whereas the main discrepancy among three datasets is located around the equatorial regions of the Intertropical Convergence Zone, the South Pacific Convergence Zone and warm cloud area, which is related with the difference between reanalysis models for the scheme of convective parameterization, the treatment of warm clouds, and the assimilation of satellite-based observations. Moreover, these CWV products are fairly consistent with observations （satellite-based retrievals） for oceans. On the other hand there are systematic underestimations about 2.5 kg/m2 over lands for all three CWV datasets, compared with radiosonde ob- servations. The difference between models to solve land-atmosphere interaction in complex environment, as well as the pauci- ty in radiosonde observations, leads to significant water vapor gaps in the Amazon Basin of South America, central parts of Africa and some mountainous regions. These results would help better understand the climatology difference among various reanalysis datasets better, and more properly choose water vapor datasets for different research requirements.
