Influence of microcylinders with different vibration laws on the flow control effect of a horizontal axis wind turbine

Abstract

Due to the flow separation on the blade of the NREL Phase VI wind turbine, a new flow control technique involving installation of an off‐surface vibrating small structure is proposed. By considering the actual flow condition, fluid‐solid coupling is applied in which two kinds of microcylinder vibration modes are set up, and the aerodynamic performance is numerically studied. The influence of the vibration modes, amplitude, and frequency of the off‐surface vibrating small structure on the aerodynamic performance is explored. For various stall conditions, the flow separation can be well suppressed by utilizing a suitable vibrating microcylinder rather than a static microcylinder. In addition, the vibrating microcylinder shows a noticeable suppression effect on large flow separation. Both the vibration direction and vibration amplitude play leading roles in the improvement of the aerodynamic performance, and a microcylinder with a high vibration frequency can more quickly suppress surface flow separation to achieve an optimum aerodynamic performance than a microcylinder with a low vibration frequency. By setting microcylinders with suitable vibration rules close to the blade surface, the wind energy coefficient can be obviously increased compared with those obtained when adding a static microcylinder or without microcylinder addition.

Investigation of leading-edge slat on aerodynamic performance of wind turbine blade

“…In the meanwhile, the influence of cylinder vibration (including vibration frequency, vibration amplitude, and vibration frequency) on blade was discussed. 27 The results showed that the wind energy coefficient of the blade equipped with a cylinder in proper vibration was significantly higher than that of the blades with a stationary cylinder. Ebrahimi and Movahhedi 28 placed the various microtabs at 95% chord edge of the blade pressure side, the placement of the microtab, and the change in the height along the blade spreading direction were discussed.…”

Numerical Modeling of Horizontal Axis Wind Turbine: Aerodynamic Performances Improvement Using an Efficient Passive Flow Control System

“…The flow separation and boundary layer control are methods aimed at improving an airfoil's aerodynamic performance, increasing the wind turbine's efficiency. In addition, these methods can adjust the wind turbine's aerodynamic load and output power under varying wind speeds and ensure the generator's safety [1].…”

“…(2) Passive control techniques that do not require auxiliary power or a control loop, such as slot [13], multi-element airfoil [14][15][16], leading-edge slat [1,17], Gurney flap [18][19][20], self-activated flaps [21], vortex generator [22][23][24], stall strips [25,26], and other airfoil configurations that can delay or even eliminate dynamic stall.…”