With the development of China's economy,the implementation scale and scope of hydraulic engineering projects are increasing,and the application of anti-seepage technology has an important influence on the construc...With the development of China's economy,the implementation scale and scope of hydraulic engineering projects are increasing,and the application of anti-seepage technology has an important influence on the construction quality of hydraulic engineering.In this paper,the significance and problems of the application of anti-seepage technology in the construction of hydraulic engineering projects were mainly analyzed,and specific application strategies were proposed.展开更多
A fuzzy robust nonlinear controller for hydraulic rotary actuators in flight motion simulators is proposed. Compared with other three-order models of hydraulic rotary actuators, the proposed controller based on first-...A fuzzy robust nonlinear controller for hydraulic rotary actuators in flight motion simulators is proposed. Compared with other three-order models of hydraulic rotary actuators, the proposed controller based on first-order nonlinear model is more easily applied in practice, whose control law is relatively simple. It not only does not need high-order derivative of desired command,but also does not require the feedback signals of velocity, acceleration and jerk of hydraulic rotary actuators. Another advantage is that it does not rely on any information of friction, inertia force and external disturbing force/torque, which are always difficult to resolve in flight motion simulators. Due to the special composite vane seals of rectangular cross-section and goalpost shape used in hydraulic rotary actuators, the leakage model is more complicated than that of traditional linear hydraulic cylinders. Adaptive multi-input single-output（MISO） fuzzy compensators are introduced to estimate nonlinear uncertain functions about leakage and bulk modulus. Meanwhile, the decomposition of the uncertainties is used to reduce the total number of fuzzy rules. Different from other adaptive fuzzy compensators, a discontinuous projection mapping is employed to guarantee the estimation process to be bounded. Furthermore, with a sufficient number of fuzzy rules, the controller theoretically can guarantee asymptotic tracking performance in the presence of the above uncertainties, which is very important for high-accuracy tracking control of flight motion simulators.Comparative experimental results demonstrate the effectiveness of the proposed algorithm, which can guarantee transient performance and better final accurate tracking in the presence of uncertain nonlinearities and parametric uncertainties.展开更多
Local scour, a non-negligible factor in hydraulic engineering, endangers the safety of hydraulic structures. In this work, a numerical model for simulating local scour was constructed, based on the open source code co...Local scour, a non-negligible factor in hydraulic engineering, endangers the safety of hydraulic structures. In this work, a numerical model for simulating local scour was constructed, based on the open source code computational fluid dynamics model Open FOAM. We consider both the bedload and suspended load sediment transport in the scour model and adopt the dynamic mesh method to simulate the evolution of the bed elevation. We use the finite area method to project data between the three-dimensional flow model and the two-dimensional(2D) scour model. We also improved the 2D sand slide method and added it to the scour model to correct the bed bathymetry when the bed slope angle exceeds the angle of repose. Moreover, to validate our scour model, we conducted and compared the results of three experiments with those of the developed model. The validation results show that our developed model can reliably simulate local scour.展开更多
This article discusses the current concepts of dam design and construction in permafrost regions. It is demonstrated that embankment dams often change their state from frozen to thawed and back during the operation pe...This article discusses the current concepts of dam design and construction in permafrost regions. It is demonstrated that embankment dams often change their state from frozen to thawed and back during the operation period. It is shown that these transitions are not always attributable to observed climate warming. Where geotechnical, hydrogeological, and permafrost conditions are complicated, proper performance of embankment dams can only be provided by adhering to a selected thermal design for, as an example, a frozen state.展开更多
The process of constructing hydraulic projects on international rivers is governed by several legal regulations, among the most important of these regulations are： the Principle of no harm, and the Principle of Prior...The process of constructing hydraulic projects on international rivers is governed by several legal regulations, among the most important of these regulations are： the Principle of no harm, and the Principle of Prior Notification, protection of the river＇s environment and the Principle of Settling the International Disputes via Peaceful Means, which is considered one of the most important principles called for by the UN Pact, as it provides for adopting the peaceful means by the member states of the organization to settle international disputes through peaceful means, in addition to an applied study on the Nile Basin＇s projects.展开更多
The Poyang Lake Hydraulic Project is a major water conservancy initiative proposed by Jiangxi Province to address several challenges,including hydrological imbalance during the lake’s dry season,water scarcity,and re...The Poyang Lake Hydraulic Project is a major water conservancy initiative proposed by Jiangxi Province to address several challenges,including hydrological imbalance during the lake’s dry season,water scarcity,and reduced navigability.In recent years,due to the weakening backwater effect from the Yangtze River mainstream,the onset of the dry season in Poyang Lake has advanced,with significantly lower water levels,resulting in ecological degradation,intensified water supply confl icts,and navigatio n obstructions in the lake region.To regulate the relationship between the river and the lake,enhance water resource carrying capacity during the dry season,and ensure integrated benefits such as water supply,irrigation,and navigation,the Poyang Lake Hydraulic Project was constructed.However,the reservoir’s water storage and regulation operations directly influence the outflow,thereby affecting local hydrodynamic conditions at the confluence section of the Yangtze River mainstream.Using a t wo-dime nsional hydrodynamic model,this paper analyzes the impact of the project under unfavorable operating scenarios by examining changes in distributary flow ratios,mainstream belt shifts,and localized flow field variations in relation to the dispatching str ategies of the hydraulic project.Model test results indicate that following the construction and operation of the project,the distributary flow ratio at the Zhangjiazhou reach of the river undergoes only minor changes,with an adjustment range within 1.3%,and there is no significant impact on mainstream position or flow velocity.Consequently,the project does not pose any substantial adverse effect on navigability.These findings provide technical support for further research into the impact s on waterwa ys and navigation conditions.展开更多
文摘With the development of China's economy,the implementation scale and scope of hydraulic engineering projects are increasing,and the application of anti-seepage technology has an important influence on the construction quality of hydraulic engineering.In this paper,the significance and problems of the application of anti-seepage technology in the construction of hydraulic engineering projects were mainly analyzed,and specific application strategies were proposed.
基金supported by the National Basic Research Program of China(No.2014CB046406)the National Natural Science Foundation of China(No.51235002)
文摘A fuzzy robust nonlinear controller for hydraulic rotary actuators in flight motion simulators is proposed. Compared with other three-order models of hydraulic rotary actuators, the proposed controller based on first-order nonlinear model is more easily applied in practice, whose control law is relatively simple. It not only does not need high-order derivative of desired command,but also does not require the feedback signals of velocity, acceleration and jerk of hydraulic rotary actuators. Another advantage is that it does not rely on any information of friction, inertia force and external disturbing force/torque, which are always difficult to resolve in flight motion simulators. Due to the special composite vane seals of rectangular cross-section and goalpost shape used in hydraulic rotary actuators, the leakage model is more complicated than that of traditional linear hydraulic cylinders. Adaptive multi-input single-output（MISO） fuzzy compensators are introduced to estimate nonlinear uncertain functions about leakage and bulk modulus. Meanwhile, the decomposition of the uncertainties is used to reduce the total number of fuzzy rules. Different from other adaptive fuzzy compensators, a discontinuous projection mapping is employed to guarantee the estimation process to be bounded. Furthermore, with a sufficient number of fuzzy rules, the controller theoretically can guarantee asymptotic tracking performance in the presence of the above uncertainties, which is very important for high-accuracy tracking control of flight motion simulators.Comparative experimental results demonstrate the effectiveness of the proposed algorithm, which can guarantee transient performance and better final accurate tracking in the presence of uncertain nonlinearities and parametric uncertainties.
基金the State Key Laboratory of Hydraulic Engineering Simulation and Safety Foundation (No. HESS-1412)the National Science Fund (No. 51179178)the 111 Project (No. B14028)
文摘Local scour, a non-negligible factor in hydraulic engineering, endangers the safety of hydraulic structures. In this work, a numerical model for simulating local scour was constructed, based on the open source code computational fluid dynamics model Open FOAM. We consider both the bedload and suspended load sediment transport in the scour model and adopt the dynamic mesh method to simulate the evolution of the bed elevation. We use the finite area method to project data between the three-dimensional flow model and the two-dimensional(2D) scour model. We also improved the 2D sand slide method and added it to the scour model to correct the bed bathymetry when the bed slope angle exceeds the angle of repose. Moreover, to validate our scour model, we conducted and compared the results of three experiments with those of the developed model. The validation results show that our developed model can reliably simulate local scour.
文摘This article discusses the current concepts of dam design and construction in permafrost regions. It is demonstrated that embankment dams often change their state from frozen to thawed and back during the operation period. It is shown that these transitions are not always attributable to observed climate warming. Where geotechnical, hydrogeological, and permafrost conditions are complicated, proper performance of embankment dams can only be provided by adhering to a selected thermal design for, as an example, a frozen state.
文摘The process of constructing hydraulic projects on international rivers is governed by several legal regulations, among the most important of these regulations are： the Principle of no harm, and the Principle of Prior Notification, protection of the river＇s environment and the Principle of Settling the International Disputes via Peaceful Means, which is considered one of the most important principles called for by the UN Pact, as it provides for adopting the peaceful means by the member states of the organization to settle international disputes through peaceful means, in addition to an applied study on the Nile Basin＇s projects.
文摘The Poyang Lake Hydraulic Project is a major water conservancy initiative proposed by Jiangxi Province to address several challenges,including hydrological imbalance during the lake’s dry season,water scarcity,and reduced navigability.In recent years,due to the weakening backwater effect from the Yangtze River mainstream,the onset of the dry season in Poyang Lake has advanced,with significantly lower water levels,resulting in ecological degradation,intensified water supply confl icts,and navigatio n obstructions in the lake region.To regulate the relationship between the river and the lake,enhance water resource carrying capacity during the dry season,and ensure integrated benefits such as water supply,irrigation,and navigation,the Poyang Lake Hydraulic Project was constructed.However,the reservoir’s water storage and regulation operations directly influence the outflow,thereby affecting local hydrodynamic conditions at the confluence section of the Yangtze River mainstream.Using a t wo-dime nsional hydrodynamic model,this paper analyzes the impact of the project under unfavorable operating scenarios by examining changes in distributary flow ratios,mainstream belt shifts,and localized flow field variations in relation to the dispatching str ategies of the hydraulic project.Model test results indicate that following the construction and operation of the project,the distributary flow ratio at the Zhangjiazhou reach of the river undergoes only minor changes,with an adjustment range within 1.3%,and there is no significant impact on mainstream position or flow velocity.Consequently,the project does not pose any substantial adverse effect on navigability.These findings provide technical support for further research into the impact s on waterwa ys and navigation conditions.
