This study investigates the effects of vortex generators (VGs) on the aerodynamic performance of a wind turbine airfoil under turbulent inflow conditions. A wind tunnel test setup was established to examine the flow control effects of VGs on the DU93-W-210 airfoil at various turbulence intensities with a Reynolds number of 1.5×105. The pressure coefficients, lift and drag coefficients, and flow separation were measured for static and dynamic conditions. Results showed that when the inflow turbulence intensity increased from 0.50% to 10.18%, VGs effectively delayed flow separation on the airfoil surface, expanding the range of angles of attack for enhanced static aerodynamic performance from 11°–17° to 11°–20°. The maximum lift coefficient increase initially rose and then decreased with higher turbulence intensity (the relative increments under the three conditions were 5.45%, 7.79%, and 6.91%). During deep stall, VGs failed to suppress separation, resulting in increased pressure drag coefficients. Dynamic tests revealed that increased turbulence intensity allowed VGs to enhance lift at wider angles of attack during the downstroke phase. The aerodynamic improvement during downstroke was significantly greater than during the upstroke phase. Flow visualization using tuft methods further validated these findings. This research provides practical guidance for optimizing wind turbine airfoil design in turbulent conditions.
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Open Access
Research Article
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The continuous development and utilization of wind energy have led to the widespread adoption of wind turbines in various environments, including offshore, on land, and near buildings. These turbines are characterized by their lightweight and high flexibility. However, the complex fluid-structure coupling characteristics of wind turbines pose significant challenges to their safety, efficiency, and stability. Visualizing the flow field around wind turbines for educational and research purposes presents considerable difficulties.
This study leverages an existing wind tunnel laboratory platform to design an experimental forest-up for visualizing the aerodynamic flow field around wind turbines. The primary objective is to provide students with a clear and intuitive understanding of wake characteristics and aerodynamic principles under various wind conditions. It also seeks to clarify the coupling flow mechanism and flow field variation laws specific to roof-mounted vertical-axis wind turbines. Moreover, this research delves into the spatio-temporal characteristics of the flow field in complex terrains and quantifies the impact of different parameters on the flow field of wind turbines. Utilizing this platform, the study introduces a hybrid teaching method for wind turbine structures aligned with the dual-carbon target. It establishes a feedback mechanism to identify and address teaching challenges, thereby promoting practical educational outcomes. The visualization experiments conducted include the wake flow fields of vertical axis and horizontal axis flow fields, as well as those situated on complex terrain and low-rise building roofs.
The experiments have significantly improved teaching quality. The use of this platform facilitates the integration of teaching resources across undergraduate and graduate levels, as well as in subject competitions, thereby improving resource utilization efficiency. One notable finding is that the blade tip vortex, formed by airflow passing through the wind turbine, hinders velocity recovery in the wake region, resulting in an axial velocity loss zone within the wind turbine structure. Moreover, the study highlights how different parameters influence the dynamic flow field characteristics of wind turbine structures. When a wind turbine is mounted on a building roof, the airflow separation from the windward eaves forms significant wind shear and turbulence intensity. This, in turn, affects the entire flow field of the roof, with the vortex wake of the wind turbine showing significant temporal and spatial variations. Similarly, when a wind turbine is located on complex terrain, the combined effects of the wake and terrain create a turbulent vortex velocity shear layer, adding complexity and variability to the surrounding flow field.
By employing visual methods, these complex mechanisms and scenarios become more accessible for educational purposes, thereby improving teaching effectiveness and quality. Cultivating new energy professionals is crucial for achieving dual-carbon goals and renewing talent in the future energy industry. Adopting new teaching methods represents a direct and effective approach to improving the quality of talent development. The platform discussed in this paper is an attempt to innovate the talent cultivation process within wind farms. However, it acknowledges that there are areas for further improvement and enhancement.
Open Access
Research Article
Issue
In the present paper, we utilize the ensemble Kalman filter (EnKF) method to optimize parameters of the turbulence model Spalart-Allramas (S-A) to simulate flow fields around three wind turbine airfoils (NACA63415, S809, and DU97W300) at the same stall degree. The optimized parameters of the medium-thickness airfoil S809 are further applied to the other two airfoils to investigate their performance on airfoils with various thicknesses. For each airfoil, comparisons to experimental data regarding the pressure coefficient distribution and separation location show that using the optimized parameters can reduce numerical errors significantly. Even though applying the optimized parameters of S809 to the other two can also considerably reduce the numerical errors, the errors are slightly larger than those obtained by the optimized parameters of their own. In addition, the model parameters with significant changes after assimilation are
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