Horizontal axis wind turbines passive flow control methods: a review

Abstract

In improving wind turbine torque and power output, the aerodynamic characteristics of wind turbines blades play an important role. Unleashing easy but efficient flow enhancement techniques over aerofoil sections used in horizontal axis wind turbines (HAWT) has become essential in the increasing demand for this source of renewable energy. These techniques or methods are primarily categorized into two kinds: active and passive. Active methods of flow control need energy expensewhereas passive flow control methods are needless of auxiliarypower. This paper investigates various passive flow control strategies that have great potential to boost the aerodynamics of blades of HAWT. The mechanisms and working principles, along with the findings from various experimental studies and CFD results for passive flow control systems are included in this article. Also, some of these studies are supported by demonstrating the lift and coefficient of drag (CD) variation with the angle of attack (AoA). The review suggests simple, cost-effective ways of improving lift and controlling the aerofoil stalling behaviors to obtain higher power efficiency for HAWT.

CFD study of active flow control around a wind turbine profile using synthetic jet

“…They are frequently affected by the undesirable phenomenon of boundary layer separation, which causes several problems such as increased drag and decreased lift, blade vibrations, and noise generation due to strong vortices in the detached zones. As a solution to this problem, several flow control techniques were used in the design of wind turbine blade (Akhter & Omar, 2021;Manerikar et al, 2021). One of these techniques is the synthetic jet actuator, which is a device that oscillates a diaphragm placed on one (or more) walls of a sealed cavity to generate a synthesized jet from the ambient fluid through an orifice or slot (Gul et al, 2014).…”

Investigation of the aerodynamic characteristics of horizontal axis wind turbine using an active flow control method via boundary layer suction

“…Distinguished from VAWT, which started late and lagged behind in research, the HAWT is the mainstream of modern large-scale commercial wind turbines due to its technical maturity and high wind energy utilization coefficient [8]. The flow separation phenomenon that occurs during the operation of wind turbines is an important factor affecting the aerodynamic performance of the wind turbine [9]. The resulting unsteady flow will lead to the fluctuation of aerodynamic load, thus reducing the lifetime of wind turbine blade [10].…”