The "reinforced concrete shield and riverbed" junction or pre-excavated pits at the end of the apron of a gate dam with supercritical flow connection mode are often damaged by foundation erosion, which not only leaves the apron in a suspended state, but may also cause the flow pattern at the end of the apron to deviate from the designed supercritical flow pattern, or even form a hydraulic jump like large-scale rolling and scouring riverbed, but there are few relevant research results. For the scenario that suspended foundation at the end of apron caused by local generalized scouring, the detailed observation and computational analysis of the flow patterns near the scour pits of different sizes at the end of the apron were carried out using physical model experiments and three-dimensional turbulence numerical modelling methods. Compared to the supercritical flow pattern at the end of the apron when the foundation is not scoured, the results show that the scour pits change the flow pattern significantly, and can be divided into three categories. The first category is the hydraulic jump upstream of the apron, the second category is the mixed flow in the scour pit and the third category is the quasi-periodic flow pattern consisting of the first two categories. The results of the flow evolution study can provide technical support for the analysis of large-scale damage to the retaining structure downstream of the dam apron, which has certain engineering application value.

In order to ensure that the conductor length of multiple parallel coils of power transformer is consistent and the current density is balanced, the structure transposition is usually carried out in the winding process. The actual operation shows that the insulation at the conductor transposition is easy to damage and leads to inter-turn short circuit fault. Aiming at the problems that the fault point is difficult to set and the electrical quantity cannot be directly detected in the actual test, this paper uses the 'field-circuit' coupling principle to take the distribution transformer with the model of S13-M-200/10, the low voltage winding is wound by two flat copper wires and the transposition point is in the middle of the winding as an example. Based on the finite element simulation software, the simulation analysis model with the same size as the physical structure is established. Through the comparison of the actual test value and the simulation analysis value of the performance parameters, on the basis of verifying the correctness of the model, the electrical characteristics and electrodynamics of the low voltage winding of the power transformer are studied when the single inter-turn short circuit occurs at the conductor transposition. The results show that when a single inter-turn short circuit occurs in the low voltage winding of the transformer, the loop current of dozens of times the rated current flows inside the short circuit ring, the fault phase current decreases slightly, and the active power loss increases sharply. Conductor transposition causes uneven distribution of axial force and radial force of the coil, and the winding is prone to instability and deformation. It is necessary to take mechanical and insulation strengthening measures at the conductor transposition.

In order to realize the effective utilization of winter idle water resources in kariz of Turpan Basin and recharge the regional groundwater, it is urgent to carry out groundwater recharge project in this area and determine the reasonable construction location and effective recharge mode. Firstly, the suitability evaluation system of groundwater recharge was constructed based on the six indexes of kariz flow, recharge source distance, aquifer permeability coefficient, groundwater depth, electromechanical well density and terrain slope. The suitability zoning of groundwater recharge was carried out by using ArcGIS spatial analysis function. Field tests were carried out in the typical recharge suitable areas to study groundwater recharge methods. The results show that there are abundant recharge water sources and storage space in the middle of Gaochang District, the north basin irrigation area of Shanshan County and the northeast part of Toksun County. The overall permeability coefficient is greater than 15m/d, which is suitable for the recharge of kariz winter leisure water. The effective recharge of groundwater can be realized by using the well irrigation method of the electromechanical well recharge, which is suitable for the recharge of the winter idle water in the study area.

For the task of condition evaluation of peaking power equipment, the monitoring indicators are defined as a set of time series, among which the complex coupling relationships need to be considered. Besides, requirements on processing time are introduced by the real-time systems. A new framework is proposed to address these problems via the technology of parallel feature extraction as well as data fusion. The time series are statistically analyzed in parallel where multiple hypothesis testing is used to select the important features. Using a defined hierarchical graph convolutional network, the related information is integrated for the final condition evaluation task. Compared with the existing models, experiments indicate that the proposed method with stronger transferability and shorter processing time has a much higher predication accuracy.

The supersaturated total dissolved gas (TDG) is mainly caused by the discharge of high dam spillway, excess oxygen production of plant photosynthesis and sharp increase in water temperature, which may directly lead to fish and aquatic organisms suffering from gas bubble disease (GBD) or even death. In order to explore the measures to mitigate the adverse effects of supersaturated TDG, under different aeration conditions, the swirl mixing aeration mode has an obvious effect on the release of supersaturated TDG, its effect is slightly stronger than that of pinhole aeration method, and the aeration rate has the greatest impact on the mass transfer coefficient of supersaturated TDG, followed by the aeration depth, and the aeration diameter is the smallest. The relationship between supersaturated TDG mass transfer coefficient and aeration rate, aeration diameter and aeration depth is obtained, respectively. The average error is within ±6.25%. The research results provide a data basis for mitigating the adverse effects of supersaturated TDG.

After a high proportion of new energy is connected to the grid, the grid security and stability are significantly increased by multiple uncertainties. In order to quickly form a power adjustment plan to maintain the source-gridload dynamic balance under the scenario of power gap caused by large fluctuations of new energy, it is urgent to quantitatively evaluate the maximum power supply capacity of the grid. In this paper, the maximum power supply capacity and the minimum section margin of important sections are taken as the optimization objective functions, and the maximum power supply capacity assessment scenario of provincial power grids is modeled with power balance, slice reserve capacity, and section margin as the constraints, and the multi-stage constrained multi-objective evolution (CMOEA-MS) algorithm and the fast non-dominated ranking genetic algorithm NSGA-Ⅱ with elite strategy are used to solve the model, respectively. The quality of the solution sets of the two algorithms is evaluated in term of three indexes of convergence, uniformity and extensiveness of the solution sets. The simulation results of example show that the CMOEA-MS model has larger super volume values and better performance in solving the model, and can effectively improve the maximum power supply capacity of the provincial grid.

The plane gate controls water storage and discharge by opening and closing, and is easily damaged by the pulsating pressure of the water flow during operation. In order to study the interaction process between the opening and closing motion of the gate and the flow through the gate, this paper firstly conducted a three-dimensional numerical simulation of the flow through the gate during the opening and closing process of the gate under different bottom edge forms. And then the Hilbert-Huang transform was used to analyze the flow through the gate, and the time-frequency-amplitude information of the signal. The information analysis and comparison found that the bottom edge of the combined gate with a forward tilt of 45° and a backward tilt of 30° is gently affected by the pulsating pressure at the bottom of the gate, and the change difference of the energy amplitude at the measuring point was the smallest, and the water flow state was relatively stable. This study can provide a reference for the analysis of the pulsating pressure of the water flow through the plane gate.

Aiming at the shortcomings of low efficiency and time-consuming when using the ANSYS parametric design language (APDL) to carry out the three-dimensional finite element design of the gate structure, this paper proposed a APDL design-analysis program based on VB, and performed nephogram results on a certain project. The results show that the program can improve the design and analysis efficiency of steel arch gate, and programmers can flexibly debug related to practical project cases, so that the designed steel arch gate can meet the needs of project construction.

Conventional and wetting triaxial experiments were carried out on coarse grained materials for dam construction with a large static and dynamic triaxial tester. The dynamic characteristics of coarse grained materials after wetting deformation were studied, and the results were compared with those of conventional triaxial dynamic experiments. The experimental results show that the dynamic characteristics of coarse grained materials are greatly affected by wetting deformation, and the dynamic performance parameters of coarse grained materials are attenuated to a certain extent. The Hardin-drnevich model parameters of the two experiments were compared and analyzed. It was found that wetting deformation had a significant effect on k₂ and λ_max, and the numerical values were attenuated, but the effects on n and k₁ were not significant.

The downstream surge chamber of a certain pumped storage power station adopts impedance with upper chamber layout. The tailrace tunnel is connected with the connecting pipe through right angle bifurcated pipe and bend. The layout type is special and the water flow conditions are complex. In order to study its hydraulic characteristics, a three-dimensional flow field mathematical model of the connecting pipe at the bottom of the surge chamber was established, and the variation law of hydraulic characteristics under different diversion ratio and confluence ratio was studied. The results show that for the resistance loss of surge chamber with complex bottom flow, the three-dimensional numerical simulation can achieve better simulation effect, and the calculation results are in good agreement with the theoretical analysis results. Because the elbow at the bottom of the surge chamber, the sudden expansion and contraction between the connecting pipe and the big well will cause additional hydraulic losses, its head loss coefficient is greater than that of the conventional impedance surge chamber, and the flow coefficient is smaller than that of the separate impedance hole.