In order to study the characteristics of the hydraulic transition process of accidental pump stoppage before and after the pipeline optimization of pumping station water delivery system, based on the actual project, Bentley Hammer software was used to establish a mathematical model of the pumping station water delivery system with two pumps in parallel units to study the effects of the most unfavorable water hammer parameters such as water hammer pressure and unit speed before and after the pipeline optimization under different two-stage valve shutdown schemes. The results show that the maximum water hammer pressure decreased by 3.76%-8.85%, the minimum water hammer pressure increased by 4.89%-8.85%, and the maximum reversal speed increased by 1.47%-81.35% after pipeline optimization; The fast shutdown time had a significant effect on the most unfavorable water hammer parameters, and the most unfavorable water hammer parameters of the pumping station water delivery system all occurred before than before the optimization after pipeline optimization. It shows that the pipeline optimization effectively improved the water hammer characteristics and the safety of the pumping station water delivery system.

A new type of MBC impellerr with a guide vane slot structure was proposed to improve the energy capture and wave reduction efficiency of Savonius-type (S-type) impeller. A multi-objective optimization algorithm combined BP neural network, NSGA-Ⅱ, numerical simulation and experimental test was used to optimize five parameters of the MBC impeller including overlap ratio, gap ratio, internal and external arc angle, internal arc radius, and guide vane size. The performance of the optimal MBC impeller was compared with that of the S-type and MB-type impellers. The results show that the prediction error of the relevant performance values is less than 10% compared to the actual values, verifying the good performance of the established prediction model. The obtained optimal parameters are: overlap ratio of 0.136, gap ratio of 0.003, internal and external arc angle of 5.23°, internal arc radius of 41.42 mm, and guide vane size of 2.83 mm. Compared with the traditional S-type impeller, the optimal MBC impeller has increased energy capture efficiency by 35.8% and wave reduction efficiency by 11%.

Based on the spillway tunnel of Kangsu Reservoir Project, the RNG turbulence model and VOF model in FLOW 3D software was used to study the flow characteristics of the spillway tunnel. The flow velocity and relative energy dissipation rate under different conditions of the original design scheme was analyzed, and compared with the model test. The reliability of the numerical simulation was verified. In view of the problems in the original design scheme, such as the water-wing in the upstream transition section of the spillway tunnel, the far drive hydraulic jump in the stilling basin, and the downstream gully flow not returning to the channel, the modified scheme was proposed. The results show that the modified scheme can effectively reduce the water wing phenomenon, and can effectively reduce the downstream gully flow velocity and the riverbed scouring by adding multi-level energy dissipation, which can provide a reference for the design.

Based on the ground radiation observation data of Hubei Huashi photovoltaic power station from April to September in 2022, the forecast accuracy of the ground radiation products of Wind Energy and Solar Energy Forecasting System of China Meteorological Administration (CMA-WSP) was evaluated. Overall, the correlation coefficient between ground solar radiation and observation in the next 5 days predicted by CMA-WSP is between 0.85 and 0.91, and the forecast effect on the first day is the best. With the increase of forecast time, the forecast accuracy gradually decreases. From the perspective of month-by-month effect, the CMA-WSP has the best effect on ground radiation forecasting in August and September, and the forecast accuracy rate in May and June is relatively low. In terms of daily changes, the CMAWSP has a relatively poor forecasting effect on ground radiation at 10:00~16:00, and is better in other periods. The prediction of ground radiation by CMA-WSP has strong seasonality. The forecast results of different times in spring are quite different, and are relatively stable in summer. The forecast effect in autumn is the most stable, and the correlation coefficient between the prediction results and observation can reach 0.92. In general, the CMA-WSP has a good effect on the ground radiation forecasting in Hubei Province, which can provide good support for the short-term forecasting of photovoltaic resources in Hubei Province.

In order to enhance the real-time flood forecasting accuracy in the Linyi River Basin, a TOPKAPI grid model was developed based on the underlying surface characteristics of the Linyi River Basin. The TOPKAPI model simulation results were corrected at different lead times using BP neural networks and LSTM models. Furthermore, a stacking approach was applied, employing the Transformer model as a secondary learning tool to refine the corrections made by BP and LSTM. The results indicate that after real-time correction with the BP and LSTM models, the improvement of the simulation accuracy of the TOPKAPI model is obvious, with better correction results for shorter lead times. Following the stacking method for secondary learning, the correction results is the best, effectively enhancing the flood forecasting accuracy in the Linyi River Basin.

Aiming at the evolution of water resources in Qiandao Lake Basin under the condition of climate change, a WEP-L distributed hydrological model was established to simulate the water cycle process in the basin during 1960-2020. The Mann-Kendall non-parametric test method and Hurst index method were used to analyze the inter-annual variation and annual distribution characteristics of the total water resources in the basin. The temporal and spatial distribution and evolution trend of water resources in Qiandao Lake Basin were evaluated. The results indicate that The WEP-L model performs well in simulation the Qiandao Lake basin, and the Nash coefficient rate is above 0.83 in the calibration period and above 0.85 in the verification period; The water yield coefficient of the whole basin ranges from 0.436 to 0.630. The annual average total water resource is 122.5×10⁸m³, equivalent to 1 176.4 mm of water depth. The annual distribution process shows a unimodal structure, and the water depth of each sub-basin ranges from 742 mm to 1 266 mm, and the spatial distribution is higher in the west and lower in the east; The annual water resources series in the basin show an insignificant upward trend, and the Hurst index is 0.86, indicating a continuous upward trend. From the perspective of monthly water resources, January and February increased significantly, the other months were not significant changes.

In order to study the dynamic response of pipe-piercing dike under seismic load, taking a dike-crossing project in Guangdong Province as the research object, considering the interaction between pipeline and soil, a three-dimensional numerical simulation model of pipeline-dike was established. The simulation of foundation boundary spring-damper was realized through secondary development. The results show that under the action of 0.1g seismic acceleration, the vertical displacement of the dike increases with the increase of the height of the dike and decreases along the axis of the dike. The maximum displacement at the top of the pipeline is greater than that at the left and right ends. The stress distribution law of the pipeline is consistent with displacement, and the maximum stress of the pipeline is proportional to the thickness of the soil cover layer. The Mises stress at each point of the midpoint section of the pipeline through the dike is the largest, and the seismic capacity of the middle section of the dike is relatively weak. The stress and displacement near the midpoint section of the pipeline in the dike should be monitored in the seismic design of the subsequent dike project. This study has important practical significance to ensure the safe and stable operation of the dike-crossing project.

In order to realize the reverse power generation operation of large-scale low-lift vertical axial flow pump, using electronic frequency conversion technology instead of mechanical frequency conversion technology, the high voltage four-quadrant frequency converter was applied to Huaiyin second station reverse frequency conversion power generation, and the grid-connected scheme and variable frequency control strategy were analyzed. At the same time, the on-site transformation was carried out to realize the stepless speed regulation of the pump power generation operation. The pump unit can be automatically tracked according to the operating conditions of optimal generating speed to achieve the maximum generating power and maximize the benefit.

Early freezing of concrete is common in the construction of water conservancy projects in northern China. Early freezing damage induces the deterioration of mechanical properties of concrete structures, which seriously affects the safety, stability and service life of engineering structures. Through laboratory uniaxial compression test and CT scan test, the influence law of freezing time and freezing temperature on the mechanical properties of concrete was analyzed, the three-dimensional pore structure of concrete at different freezing time was reconstructed, the pore distribution and pore structure characteristic parameters of concrete at different freezing time were studied, and the correlation analysis between mechanical properties and pore structure of early frozen concrete was carried out. The results show that with the delay of freezing time, the porosity of concrete test blocks increases first and then decreases, the average pore surface area decreases first and then increases, the average pore diameter increases with the trend of quadratic parabola, and the average pore shape factor increases first and decreases then increases and decreases. The correlation between the average pore surface area and the compressive strength and elastic modulus of early frozen concrete is the best. It is suggested that the average pore surface area should be preferred to construct the mesoscopic damage index of early frozen concrete. Relevant research results provide support for revealing the macro and micro damage mechanism of early frozen concrete.

Taking the section of Hunan in Xiangjiang River Basin (XRB) as an example, bases on the land use and evapotranspiration data in 2000, 2010 and 2020, this study discusses the characteristics of land use type, area change and mutual conversion in the XRB by using the methods of land use transfer matrix, integrated and single dynamic attitude model and GIS spatial analysis. The effects of land use type, area and conversion on evapotranspiration in the study area were revealed. The results show that the area, proportion and spatial pattern of land use types in the XRB have undergone great changes, especially the frequent conversion among land use types. However, in the past 20 years, the order of main land use areas in the XRB remained stable: forest > farmland > grassland > construction land > water area. The order of theoretical annual evapotranspiration based on land use type in the XRB is forest > grassland > farmland > construction land, which is different from the order of actual annual total evapotranspiration based on land use area: forest > farmland > grassland > construction land. Therefore, the land use type and land use area to evapotranspiration in the study area should be considered comprehensively. The conversion of different land use types in the XRB caused the change of evapotranspiration in different trends and degrees. The conversion between construction land and other land use types has a relatively large impact on evapotranspiration in the study area, while the conversion of other land use types has a small impact on regional evapotranspiration. The research results can provide scientific reference for land use planning and water resources management in the basin.