Dynamic Stall of a Vertical-Axis Wind Turbine and Its Control Using Plasma Actuation

Abstract

In this paper, a dynamic stall control scheme for vertical-axis wind turbine (VAWT) based on pulsed dielectric-barrier-discharge (DBD) plasma actuation is proposed using computational fluid dynamics (CFD). The trend of the wind turbine power coefficient with the tip speed ratio is verified, and the numerical simulation can describe the typical dynamic stall process of the H-type VAWT. The tangential force coefficient and vorticity contours of the blade are compared, and the regular pattern of the VAWT dynamic stall under different tip speed ratios is obtained. Based on the understanding the dynamic stall phenomenon in flow field, the effect of the azimuth of the plasma actuation on the VAWT power is studied. The results show that the azimuth interval of the dynamic stall is approximately 60° or 80° by the different tip speed ratio. The pulsed plasma actuation can suppress dynamic stall. The actuation is optimally applied for the azimuthal position of 60° to 120°.

Optimization of the hydrodynamic performance of a vertical Axis tidal (VAT) turbine using CFD-Taguchi approach

“…The pressure coefficient (Qp) and the moment coefficient (Ct) around a single blade (leading blade) are calculated using the CFD data and the results show that the optimized turbine produces a promising improvement in power output.The variations of moment coefficient (Ct) with azimuthal angle for the baseline and optimized models at λ= 1.25 are calculated and the results are presented in Figure15. The results show that in the first half rotation, a significant part of positive moment contributions is located in the region between 40 ° and 180° and this is a very general characteristic demonstrated in several previous research[69,70]. Although the maximum (Ct) in some parts of the graph (40-100 o ) of the baseline model is higher than that in the optimized model, however the combination of the cambered-blade and twisted model has advantages when the whole region is considered.…”

Experimental and Numerical Analysis of the Effect of Vortex Generator Installation Angle on Flow Separation Control

“…Specifically, flow separation on the airfoil suction surface close to the blade root occurs during the operation of the wind turbine, reducing the capture power of the wind turbine [2]. To address this, researchers have proposed many methods to suppress flow separation for airfoil blades including microflaps [3], blowing and suction [4], microtabs [5], flexible walls [6], synthetic jets [7,8], plasma actuators [9,10], and VG [11,12]. Barlas [13] and Johnson [14] compared and analyzed the flow control effects of each of these different methods.…”

Analysis of the Effect of Vortex Generator Spacing on Boundary Layer Flow Separation Control

“…During the operation of wind turbines, flow separation occurs at the blade root, which reduces the wind turbine efficiency [1]. Flow control technologies, such as VGs [2], plasma flow control [3], microflaps [4], microtabs [5], blowing and suction [6], synthetic jets [7], and flexible walls [8], have been increasingly applied to the design or optimization of wind turbine blades, aiming to improve their aerodynamic performance. Barlas [9] and Johnson [10] compared these flow control methods, while Lin [11] and Wang [12] found that VGs are one of the most effective devices for improving the aerodynamic performance of blades.…”