The influence of wind turbine airfoil trailing edge thickness on aerodynamics and aerodynamic noise characteristics was studied using the computational fluid dynamics (CFD)/ Ffowcs Williams–Hawkings (FW–H) method in the present work. First, the airfoil of a DU97-W-300-flatback airfoil was chosen as the research object, and numerical method validation was performed. Three kinds of turbulence calculation methods (unsteady Reynolds average Navier-Stokes (URANS), detached eddy simulation (DES), and large eddy simulation (LES)) were investigated in detail, and three sets of grid scales were used to study the impact of the airfoil on the aerodynamic noise. Secondly, the airfoil trailing edge thickness was changed, and the impact of trailing edge thickness on aerodynamics and aerodynamic noise was investigated. Results show that three kinds of turbulence calculation methods yield the same sound pressure frequency, and the magnitude of the sound pressure level (SPL) corresponding to the mean frequency is almost the same. The calculation of the SPL of the peak value and the experimental results can match well with each other, but the calculated core frequency is slightly lower than the experimental frequency. The results of URANS and DES are closer to each other with a changing trend of SPL, and the consequences of the DES calculation are closer to the experimental results. From the comparison of two airfoils, the blunt trailing edge (BTE) airfoil has higher lift and drag coefficients than the original airfoil. The basic frequency of lift coefficients of the BTE airfoil is less than that of the original airfoil. It is demonstrated that the trailing vortex shedding frequency of the original airfoil is higher than that of the BTE airfoil. At a small angle of attack (AOA), the distribution of SPL for the original airfoil exhibits low frequency characteristics, while, at high AOA, the wide frequency characteristic is presented. For the BTE airfoil, the distribution of SPL exhibits low frequency characteristics for the range of the AOA. The maximum AOA of SPL is 4° and the minimum AOA of SPL is 15°, while, for the original airfoil, the maximum AOA of SPL is 19°, and the minimum AOA is 8°. For most AOAs, the SPL of the BTE airfoil is larger than that of the original airfoil.

Considering environmental sustainability, ecological embankments are often adopted in rivers, which benefit both the erosion resistance and the ecological balance of the bank. In this paper, the effectiveness of different types of dominant grass species in ecological slope protection and their impact mechanisms, as well as the impact of non-directional inflow on erosion characteristics, were investigated. Based on the principle of similarity theory in hydraulic modeling and the characteristics of flood erosion in riverbanks, a test model system for hydraulic ecological simulation was designed, including a vegetation bank slope and channels. Three types of dominant grass species were selected, and 12 series of erosion experiments were conducted in the grassed slope of the test model. Three types of root–soil composites and a reference plain soil were involved in the tests, and soil mechanical indicators such as shear strength were collected. Experimental results show that root–soil composite is a special elastic–plastic material, which provides additional cohesive force to the soil due to its root consolidation and reinforcement effects, Δc. The shear strength index reflecting soil cohesion was increased by 15% to 20%. The primary factor affecting slope erosion is the flushing velocity, and both the average erosion depth and the unit soil erosion loss present an exponential function with respect to this factor, while presenting a linear function with the angle of incoming flow. Compared with the plain soil slope, the ecological slope could decrease erosion significantly. The sand loss of the ecological slope is only 50~60% that of the plain soil slope as the flushing velocity is 3–4 m s⁻¹. In vertical flushing, the sand loss in the plain soil slope is 1.73–2.43 times that of the ecological slope. This research might provide technical support for the anti-scourability design of the ecological embankment.

For large-scale constructed wind farms, reducing wake loss and improving the overall output power are the main objectives for their optimal operation. Therefore, a wind farm power maximization method based on a multi-strategy improved sparrow search algorithm (MS-ISSA) is proposed in this paper. Integrating the wake propagation mechanism of wind turbines and the characteristics of the classic Jensen wake model, the Jensen–Gaussian wake model and wake superposition model were constructed to accurately calculate the wind farm wake distribution. The constructed Jensen–Gaussian wake model and wake superposition model can accurately describe the non-uniform distribution characteristics of wake velocity. The Sin chaotic model, Cauchy distribution, and hyperparameter adaptive adjustment strategy were used to improve the sparrow search algorithm (SSA), and the optimization ability, convergence speed, and stability of the SSA were improved. Accordingly, considering the maximum output power of the wind farm as the optimization target and axial induction factor as the optimization variable, a coordinated optimization model for wind turbines based on MS-ISSA was proposed to realize the coordinated optimal operation of wind turbines with reduced wake loss. Considering the Danish Horns Rev wind farm as the research object, the results of optimization using particle swarm optimization algorithm, whale optimization algorithm, basic sparrow search algorithm, and MS-ISSA were calculated and analyzed. The calculation results revealed that under different incoming wind conditions, the MS-ISSA exhibited better optimization results than the other optimization algorithms.

Owing to the high tidal range, the Severn Estuary and Bristol Channel have the potential to generate huge amounts of renewable electricity for the UK. During the flood tide, the surging water travels upstream to form the Severn Bore. This study explores the dynamics of the Severn Bore through hydrodynamic modelling, analyzing how the tidal amplitude, mean water level, and river discharge affect the bore’s intensity, reach, and sustainability. The Delft3D simulations show that the downstream tidal amplitude plays a critical role. Tides with an amplitude of less than 6 m will lead to the disappearance of the Severn Bore. The mean water level also significantly influences the bore’s propagation, with a 1.5 m drop resulting in a 15 km retreat of the bore. A high river discharge rate weakens the bore’s intensity and reduces its reach. These findings underscore the need for careful planning in tidal energy development within the Severn Estuary. Excessive exploitation of tidal energy can be detrimental to the Severn Bore and the ecological function of the estuary.

The geometry of non-pressurized tunnel intersections governs the hydraulic behavior of the confluence flows, which are critical to the safe operation of pumped storage power stations. To address the issue of water surface levels exceeding the permissible height of the vertical walls at the intersection of the sediment discharge and emptying tunnels close to the lower reservoir of a pumped storage power station, a hydraulic model with a scale of 1:45 was constructed to optimize the intersection design. The optimization process included replacing the straight connection with an arc connection, incorporating an energy dissipation basin into the emptying tunnel, reducing the intersection angle, and increasing the arc radius. During the optimization, the hydraulic behavior of the confluence flow was thoroughly analyzed. This study determined that an arc connection with a 21° intersection angle represented the optimal design. Using the RNG k-ε turbulence model and the volume-of-fluid (VOF) method, a three-dimensional (3D) numerical model was developed to further evaluate the flow patterns, velocity fields, and bottom pressure distributions under both the optimized-design and model-verification conditions. The numerical simulation results, validated against experimental data, exhibited close agreement. The findings demonstrate that the optimized design ensures compliance with specifications, as the maximum water depth no longer exceeds the height of the straight walls. This study offers valuable insights for optimizing tunnel intersections of high-elevation-difference non-pressurized tunnels in pumped storage power stations.