Dynamic separation on a pitching and surging airfoil as a model for flow over vertical axis wind turbine blades
نویسنده
چکیده
Vertical axis wind turbine (VAWT) blades undergo dynamic separation due to the large angle of attack variation they experience during a turbine rotation. The flow over a single blade was modeled using a sinusoidally pitching and surging airfoil in a constant free stream flow at a mean chord Reynolds number of 10. Two-dimensional, time resolved velocity fields were acquired using particle image velocimetry (PIV). Vorticity contours were used to visualize shear layer and vortex activity. A low order model of dynamic separation was developed using Dynamic Mode Decomposition (DMD). A primary and secondary dynamic separation mode were identified as the critical drivers for the unsteady flow field.
منابع مشابه
Leading Edge Vortex Development on Pitching and Surging Airfoils: A Study of Vertical Axis Wind Turbines
Vertical axis wind turbine blades undergo dynamic stall due to the large 1 angle of attack variation they experience during a turbine rotation. Particle image 2 velocimetry on a pitching and surging airfoil was used to perform time resolved 3 measurements at blade Reynolds numbers near turbine operating conditions of 105. 4 These experiments were compared to simulations performed in the rotatin...
متن کاملScaling of Vertical Axis Wind Turbine Dynamic Stall
Vertical axis wind turbines (VAWT) are an alternative to horizontal axis wind turbines (HAWT) for wind and tidal energy harvesting applications. Studies of vertical axis wind turbines have heavily invested in understanding the behaviour of the complete turbine, but often with only cursory assessment of the contributions of unsteady aerodynamics of individual blades. This paper experimentally ex...
متن کاملDesign and Implementation of the Rotor Blades of Small Horizontal Axis Wind Turbine
Since the renewable resources of energy have become extremely important, especially wind energy, scientists have begun to modify the design of the wind turbine components, mainly rotor blades. Aerodynamic design considered a major research field related to power production of a small horizontal wind turbine, especially in low wind speed locations. This study displays an approach to the selectio...
متن کاملEffect of Amplitude and Mean Angle of Attack on the Unsteady Surface Pressure of a Pitching Airfoil
Details of pressure distributions, on a two dimensional airfoil oscillating in pitch through stall, in a 0.8 0.8 m low-speed wind tunnel are presented. Pitching occurred about the airfoils quarter-chord axis. Pitch rate, Reynolds number, and oscillation amplitudes were varied to determine the effects on pressure and lift distributions. It was found that mean angle of attack and pitching amplitu...
متن کاملNumerical Analysis of the Performance of the DU91-W2-250 Airfoil for Straight-Bladed Vertical-Axis Wind Turbine Application
This paper presents a numerical analysis of the performance of a three-bladed Darrieus vertical-axis wind turbine based on the DU91-W2-250 airfoil. A complete campaign of 2-D simulations, performed for several values of tip speed ratio and based on RANS unsteady calculations, has been performed to obtain the rotor torque and power curves. Rotor performances have been compared with the results o...
متن کامل