In this study, the performance of offshore wind turbines at low tip speed ratio (TSR) is studied using computational fluid dynamics (CFD), and the performance of offshore wind turbines at low tip speed ratio (TSR) is improved by revising the blade structure. First, the parameters of vertical axis offshore wind turbine are designed based on the compactness iteration, a CFD simulation model is established, and the turbulence model is selected through simulation analysis to verify the independence of grid and time step. Compared with previous experimental results, it is shown that the two-dimensional simulation only considers the plane turbulence effect, and the simulation turbulence effect performs more obviously at a high tip ratio, while the three-dimensional simulation turbulence effect has well-fitting performance at high tip ratio. Second, a J-shaped blade with optimized lower surface is proposed. The study showed that the optimized J-shaped blade significantly improved its upwind torque and wind energy capture rate. Finally, the performance of the optimized J-blade offshore wind turbine is analyzed.

In this study, the structure of the trailing edge of the vertical axis offshore wind turbine blade is modified. First, according to the method of parameterization, the offshore wind turbine model is established, and a series of characteristics of the offshore wind turbine are obtained. Second, we add flaps with different lengths to the trailing edge of NACA0021 airfoil to obtain different dynamic characteristics. The angle of the additional trailing edge flaps is modified. Finally, a simulation model for the modified airfoil of the vertical axis offshore wind turbine is reestablished, and the variable characteristics of the performance is studied. Through the optimization and analysis of the blade structure, this study has obtained the best parameters of the length and angle of the offshore wind turbine blade trailing edge flap. The optimization of the blade structure changes the flow field around the blade, which significantly improves the maximum wind energy capture rate and self-starting ability of the vertical axis offshore wind turbine.

Recently, hexagonal ferrites (hexaferrites) have attracted increasing attention for high-performance microwave absorption owing to their favorable magnetic and dielectric properties. However, their natural resonance in the GHz region limits their application in narrow-band high-frequency absorbers. Herein, Ce³⁺-doped BaCo₂Fe₁₆O₂₇(CBCF) hexagonal ferrite sheets with varying Ce concentrations were successfully synthesized via a sol–gel method combined with high-temperature calcination. With increasing Ce³⁺ content, the diffraction peaks shifted towards higher angles, and the magnetic parameters of the W-type hexaferrite were effectively improved. The saturation magnetization increased from 75.66 to 83.73 emu/g. Notably, the Ce_0.075Ba_0.925Co₂Fe₁₆O₂₇(C_0.075BCF) sample exhibited excellent broadband absorption performance, achieving a minimum reflection loss (RL) of −18.40 dB at 14.92 GHz and an effective absorption bandwidth of 5.52 GHz. The microwave absorption performance was effectively controlled by tuning the natural resonance frequency of the W-type hexaferrite via Ce doping. This study provides a new strategy for designing broadband microwave absorbers by modulating the natural resonance frequency.