The virtual prototype technology is applied to the design of the hydraulic impingement shovel, which is to increase the reliability of the design. The work principle of hydraulic impingement shovel is expatiated, and ...The virtual prototype technology is applied to the design of the hydraulic impingement shovel, which is to increase the reliability of the design. The work principle of hydraulic impingement shovel is expatiated, and its dynamic equations are established. The 3D model of virtual prototype is built by PRO/E. Then the couple between the mechanical body of prototype and the hydraulic system is completed by virtue of ADAMS. Finally, the simulation is made on the virtual prototype. The simulation results show that the design of underwater hydraulic impingement shovel is rational. The virtual prototype technology could lay sound foundation of successful manufacturing of physical prototype for the first time and offer highly effective and feasible means for the design and production of underwater equipments.展开更多
Debris flows form deposits when they reach an alluvial fan until they eventually stop.However,houses located in the alluvial fan might affect the debris flow flooding and deposition processes.Few previous studies have...Debris flows form deposits when they reach an alluvial fan until they eventually stop.However,houses located in the alluvial fan might affect the debris flow flooding and deposition processes.Few previous studies have considered the effects of houses on debris flow flooding and deposition.This study conducted model experiments and numerical simulations using the Kanako2D debris flow simulator to determine the influence of houses on debris flow flooding and deposition.The model experiments showed that when houses are present,the debris flow spreads widely in the cross direction immediately upstream of the houses,especially when the flow discharge is large or the grain size is small.Houses located in the alluvial fan also influence the deposition area.The presence of houses led to flooding and deposition damage in some places and reduced the damage in others.The simulation also demonstrated the influence of houses.Both the model experiment and the simulation showed that houses change the flooding and deposition areas.展开更多
The erosion mechanisms of abandoned coastal section are understood detailedly by flume experiment, which play an important role to the offshore engineering facilities. A movable-bed physical model has been used to inv...The erosion mechanisms of abandoned coastal section are understood detailedly by flume experiment, which play an important role to the offshore engineering facilities. A movable-bed physical model has been used to investigate the coastal erosion of an abandoned section of the Huanghe （Yellow） River Delta. The theory of physical scale models is discussed and a method for constructing the representative seabed section is developed. The results indicate that during the period initially after the abandonment of the delta the entire bed experienced rapid erosion because the seabed was steep and prone to liquefaction that resulted from storm wave action. After this initial period, a balance of erosion and accretion was established, and the beach profllc equilibrated with a point of balance present on the profile. The experimental results indicate that the volume of deposition was about half that of the erosion. Wave action may also induce significant stratal changes through its interaction with the soft seabed. The major morphological features developed in the model delta section were found to be qualitatively comparable with those observed in the prototype. A distorted modeling law that maintains the similarity of the modeled and prototype equilibrium beach profiles is proposed. Experimental results show that the distorted modeling is able to reproduce the beach-face slope in nature, and the model also successfully reproduced three historical evolutionary stages of erosion.展开更多
Focused underwater plasma sound sources are being applied in more and more fields. Focusing performance is one of the most important factors determining transmission distance and peak values of the pulsed sound waves....Focused underwater plasma sound sources are being applied in more and more fields. Focusing performance is one of the most important factors determining transmission distance and peak values of the pulsed sound waves. The sound source’s components and focusing mechanism were all analyzed. A model was built in 3D Max and wave strength was measured on the simulation platform. Error analysis was fully integrated into the model so that effects on sound focusing performance of processing-errors and installation-errors could be studied. Based on what was practical, ways to limit the errors were proposed. The results of the error analysis should guide the design, machining, placement, debugging and application of underwater plasma sound sources.展开更多
Residence time is an important indicator for river environmental management.In this paper,a 3D hydrodynamic model has been successfully applied to Little Manatee River to characterize the mixing and transport process ...Residence time is an important indicator for river environmental management.In this paper,a 3D hydrodynamic model has been successfully applied to Little Manatee River to characterize the mixing and transport process and residence time.The model employs horizontal curvilinear orthogonal grids to represent the complex river system that consists of branches and bayous.The model has been satisfactorily calibrated and verified by using two continuous data sets.The data sets consist of hourly observations of all forcing boundaries,including freshwater inputs,tides,winds,salinity and temperatures at bay boundary,and air temperatures for model simulations.The data sets also consist of hourly observations of water levels,salinity,and temperature at several river stations.The calibrated and verified hydrodynamic model was used to predict residence time in the Little Manatee River.Under the minimum flow of 0.312 m3/s,the pulse residence time(PRT) is 108 days.Model simulations were also conducted for 17 flow scenarios.Empirical regression equations have been satisfactorily derived to correlate PRT to freshwater inflow.Correlation coefficient R2 is 0.982 for PRT.展开更多
The hydrogeology of first-order streams have been evaluated from 2007 to 2009 as part of the Whitetail Basin Watershed Restoration Project in Hay Creek Canyon located 25 km north of Whitehall Montana, USA. An in-depth...The hydrogeology of first-order streams have been evaluated from 2007 to 2009 as part of the Whitetail Basin Watershed Restoration Project in Hay Creek Canyon located 25 km north of Whitehall Montana, USA. An in-depth study of the riparian area hydrogeology started in the fall of 2007 with the installation of more than 40 hand-augered deeper （〉 1 m） wells to complement preexisting driven metal pipe piezometers （± 1 m） installed in four first-order drainages. Two zones within the shallow alluvial systems were identified. This paper presents the results of a concentrated study conducted in the Hay Creek drainage within the tWO zones. Data loggers placed in some of the wells led to a gradual understanding of the water-level patterns in different vegetative types （Douglas Fir, Aspen, Willow-Alder. and Grass-Sagebrush） over the various seasons. The deeper water-level responses change from seasonal patterns to strongly diurnal during summer months. Diurnal patterns continue until leaves drop from riparian vegetation. This was expected, however, the Douglas fir trees show the same pattern. Near the end of the study a full year of water-level data showing the seasonal behavior changes were collected. Resaturation of the upper zone occurs in the fall with sources of recharge coming from up-drainage. A detailed evaluation of water-level responses from up-drainage to down-drainage piezometers occurs in a ＂wave-like＂ resaturation phenomenon that allows one to estimate the bulk hydraulic conductivity of the ＂alluvial system＂ aquifer using principles of Darcy＇s Law. The methods used to evaluate the hydraulic properties and seasonal water-level patterns are presented.展开更多
基金Supported by 863 Program Item of Hi-tech Research Development Program of China Foundation under Grant No.2002AA602012-1.
文摘The virtual prototype technology is applied to the design of the hydraulic impingement shovel, which is to increase the reliability of the design. The work principle of hydraulic impingement shovel is expatiated, and its dynamic equations are established. The 3D model of virtual prototype is built by PRO/E. Then the couple between the mechanical body of prototype and the hydraulic system is completed by virtue of ADAMS. Finally, the simulation is made on the virtual prototype. The simulation results show that the design of underwater hydraulic impingement shovel is rational. The virtual prototype technology could lay sound foundation of successful manufacturing of physical prototype for the first time and offer highly effective and feasible means for the design and production of underwater equipments.
基金supported by JSPS KAKENHI(Grant No.24710206),Grant-in-Aid for Young Scientists (B)
文摘Debris flows form deposits when they reach an alluvial fan until they eventually stop.However,houses located in the alluvial fan might affect the debris flow flooding and deposition processes.Few previous studies have considered the effects of houses on debris flow flooding and deposition.This study conducted model experiments and numerical simulations using the Kanako2D debris flow simulator to determine the influence of houses on debris flow flooding and deposition.The model experiments showed that when houses are present,the debris flow spreads widely in the cross direction immediately upstream of the houses,especially when the flow discharge is large or the grain size is small.Houses located in the alluvial fan also influence the deposition area.The presence of houses led to flooding and deposition damage in some places and reduced the damage in others.The simulation also demonstrated the influence of houses.Both the model experiment and the simulation showed that houses change the flooding and deposition areas.
基金Supported by The National Basic Research Program (973 Program) (Nos. 2005CB422304 and 2002CB412408)
文摘The erosion mechanisms of abandoned coastal section are understood detailedly by flume experiment, which play an important role to the offshore engineering facilities. A movable-bed physical model has been used to investigate the coastal erosion of an abandoned section of the Huanghe （Yellow） River Delta. The theory of physical scale models is discussed and a method for constructing the representative seabed section is developed. The results indicate that during the period initially after the abandonment of the delta the entire bed experienced rapid erosion because the seabed was steep and prone to liquefaction that resulted from storm wave action. After this initial period, a balance of erosion and accretion was established, and the beach profllc equilibrated with a point of balance present on the profile. The experimental results indicate that the volume of deposition was about half that of the erosion. Wave action may also induce significant stratal changes through its interaction with the soft seabed. The major morphological features developed in the model delta section were found to be qualitatively comparable with those observed in the prototype. A distorted modeling law that maintains the similarity of the modeled and prototype equilibrium beach profiles is proposed. Experimental results show that the distorted modeling is able to reproduce the beach-face slope in nature, and the model also successfully reproduced three historical evolutionary stages of erosion.
基金Supported by the National Natural Science Foundation under Grant No.60572098
文摘Focused underwater plasma sound sources are being applied in more and more fields. Focusing performance is one of the most important factors determining transmission distance and peak values of the pulsed sound waves. The sound source’s components and focusing mechanism were all analyzed. A model was built in 3D Max and wave strength was measured on the simulation platform. Error analysis was fully integrated into the model so that effects on sound focusing performance of processing-errors and installation-errors could be studied. Based on what was practical, ways to limit the errors were proposed. The results of the error analysis should guide the design, machining, placement, debugging and application of underwater plasma sound sources.
基金supported by the Southwest Florida Water Management District
文摘Residence time is an important indicator for river environmental management.In this paper,a 3D hydrodynamic model has been successfully applied to Little Manatee River to characterize the mixing and transport process and residence time.The model employs horizontal curvilinear orthogonal grids to represent the complex river system that consists of branches and bayous.The model has been satisfactorily calibrated and verified by using two continuous data sets.The data sets consist of hourly observations of all forcing boundaries,including freshwater inputs,tides,winds,salinity and temperatures at bay boundary,and air temperatures for model simulations.The data sets also consist of hourly observations of water levels,salinity,and temperature at several river stations.The calibrated and verified hydrodynamic model was used to predict residence time in the Little Manatee River.Under the minimum flow of 0.312 m3/s,the pulse residence time(PRT) is 108 days.Model simulations were also conducted for 17 flow scenarios.Empirical regression equations have been satisfactorily derived to correlate PRT to freshwater inflow.Correlation coefficient R2 is 0.982 for PRT.
文摘The hydrogeology of first-order streams have been evaluated from 2007 to 2009 as part of the Whitetail Basin Watershed Restoration Project in Hay Creek Canyon located 25 km north of Whitehall Montana, USA. An in-depth study of the riparian area hydrogeology started in the fall of 2007 with the installation of more than 40 hand-augered deeper （〉 1 m） wells to complement preexisting driven metal pipe piezometers （± 1 m） installed in four first-order drainages. Two zones within the shallow alluvial systems were identified. This paper presents the results of a concentrated study conducted in the Hay Creek drainage within the tWO zones. Data loggers placed in some of the wells led to a gradual understanding of the water-level patterns in different vegetative types （Douglas Fir, Aspen, Willow-Alder. and Grass-Sagebrush） over the various seasons. The deeper water-level responses change from seasonal patterns to strongly diurnal during summer months. Diurnal patterns continue until leaves drop from riparian vegetation. This was expected, however, the Douglas fir trees show the same pattern. Near the end of the study a full year of water-level data showing the seasonal behavior changes were collected. Resaturation of the upper zone occurs in the fall with sources of recharge coming from up-drainage. A detailed evaluation of water-level responses from up-drainage to down-drainage piezometers occurs in a ＂wave-like＂ resaturation phenomenon that allows one to estimate the bulk hydraulic conductivity of the ＂alluvial system＂ aquifer using principles of Darcy＇s Law. The methods used to evaluate the hydraulic properties and seasonal water-level patterns are presented.
