The independent meso-scale weather research and forecasting (WRF) model neglects the modulation effects of sea surface deformation on the turbulent structure of the three-dimensional wind field. This sea surface deformation is induced by wave propagation and ocean current evolution. Consequently, the WRF model cannot output second-scale fluctuating wind speeds. To address this problem, this paper establishes a coupled meso-micro-scale multi-layer nested wind-wave-current numerical simulation method. This method is based on the WRF model, simulating waves nearshore (SWAN), regional ocean modeling system (ROMS) and large eddy simulation coupling framework (WRF-SWAN-ROMS-LES). Additionally, a coupled software platform, Marine_CFD, is developed to enable mesoscale forcing-driven meso-micro-scale coupling. Using this method, we conduct a comparative analysis of wind speed simulation performance among three models. These models include the meso-scale air-sea coupled atmospheric model, namely the coupled ocean-atmosphere-wave-sediment transport (COAWST) model, and the standalone atmospheric models, namely the WRF model and the WRF_SST model. The effectiveness of the micro-scale large eddy simulation in reproducing turbulent fluctuations is also verified. The results indicate that the wind-wave-current coupled model achieves higher accuracy in characterizing the evolutionary process of offshore wind speeds. At the height of 38 m, the Pearson correlation coefficient of the COAWST model increases to 0.789. This value is higher than those of the WRF model (0.733) and the WRF_SST model (0.735). This improvement demonstrates that the COAWST model possesses a distinct advantage in simulating the evolution of marine wind speeds. In the micro-scale simulation, the three-dimensional spatiotemporal fields of velocity, potential temperature, and pressure are extracted from the meso-scale atmospheric output. These fields are then employed to drive the micro-scale large eddy simulation. The resulting wind speed time series are overall situated in the middle region of the fluctuating wind speed curve generated by the large eddy simulation. Moreover, these time series can effectively retain the high-frequency fluctuating characteristics at the second scale.

Aerodynamics is the primary and key issue faced by wind energy engineering, which determines its economy, stability and safety. Based on the development requirement and trend of large-scale, clustering, oceanic, intelligence and digital for wind engineering, the present review is mainly focused on the aerodynamics issues faced by wind energy, such as the atmospheric boundary layer (ABL), wind turbine wake flow, onshore/offshore/complex-terrain wind farm flow and its interactions. As the second review of a successive work, special interests here are put on the atmospheric inflow and wake characteristics of wind turbines. For these two aspects, this paper summarizes recent research efforts in field measurement, wind tunnel experiment, theoretical analysis, numerical simulation, engineering modelling and artificial intelligence predictions, and also provides some views on the corresponding flow distribution characteristics, evolution laws and key mechanisms. Some discussions and suggestions are made on the aerodynamic challenges faced by wind power development under our country’s specific atmospheric/geographical conditions. Finally, a non-exhaustive perspective on the future of wind energy engineering research is presented. It is expected to provide an important reference for wind power industry planning, technological development and project implementation.

As wind turbine blades reach the 100-meter-scale, the blade size and flexibility keep increasing, which makes the geometric nonlinear effect on the structural dynamic response of the blade more severe. In order to solve the problem of nonlinear aero-elastic calculation of highly flexible blades, an aeroelastic analysis method for highly flexible blades has been established by coupling the Legendre spectral finite element based geometrically exact beam theory and the blade element momentum theory. The calculation result of a curved beam agrees well with the analytical solution, validating the prediction accuracy of the geometrically exact beam theory. By taking the NREL 5 MW and IEA 15 MW wind turbines as examples, the linear and nonlinear dynamic response of a 61.5 m blade and a 117 m blade under both steady-state and turbulent wind conditions are calculated. The results show that, for the 5 MW and 15 MW wind turbines, due to the negligence of the nonlinear effect, the numerical differences of the flapwise tip deflection and the flapwise root moment are increased by 21.35% and 21.23%, respectively, and there is also a 3.2% difference in the frequency of the first edgewise mode. The nonlinear effect of the 100-meter-scale blades has a great impact on the aeroelastic characteristics such as the blade dynamic response and the edgewise mode, thus it should be fully considered in the blade design to ensure the operational safety of wind turbines.

With the establishment of national policies around the world, the development of wind industry has been entering its heyday. Wind turbine systems are continuously upsized from megawatt level to multi-megawatt class, deployed for both onshore wind power and offshore wind power in diverse sea conditions, intelligentized with smart materials, structures and control strategies, and digitized with precise prediction and state-aware control system. These mainstream trends for wind energy development, in the meanwhile, raise tremendous challenging issues for wind energy research and development. Among them, wind turbine aerodynamics will face new problems and great challenges. As the first review of a sucessive work, this study is mainly focused on the aerodynamics of horizontal-axis wind turbines. An explanation for the aerodynamic complexity is addressed at first. Then, research progress on key aerodynamics issues, such as the aerodynamic characteristics of wind turbine airfoils and blades, as well as modern wind turbine design (special focus is put on the offshore wind power technology and the inevitable typhoon phenomenon, together with the experienced aeroelastic problem caused by the increasement in wind turbine size) and new flow control strategies are discussed. In this process, recent theoretical, experimental, and numerical studies that have contributed to improve our understanding of wind turbine aerodynamic performance, such as aerodynamic forces, flow fields and flow mechanism, are summarized. Additionally, the strength and limitation of these research approaches are discussed. Possible future research trend is analyzed and prospected, providing some references for large-scale wind turbine blade design.