Numerical study of the effects of wind shear coefficients on the flow characteristics of the near wake of a wind turbine blade

Abstract

This study investigates the effects of wind shear and wind shear coefficients on the near wake of a wind turbine. A wind turbine is subjected to the effects of wind shear, which leads to unsteady performance of the blade and characteristics of the blade near the wake. Wind shear coefficients of 0.1, 0.2, and 0.3 are used. The results are obtained using the three-dimensional incompressible Reynolds-Averaged Navier-Stokes equations, and the turbulence, are simulated via the shear-stress transport k–ω turbulence model. The flow of the air and, in particular, the axial velocity and tangential velocity are strongly affected by the rotation in the region of the blade near wake. There is an obvious velocity deficit at the near wake when the air flows over the blade, and this velocity deficit gradually decreases as the air flows downstream. The torque of the blade and the characteristics of the blade near wake periodically change with the effect of wind shear. The axial, tangential, and radial velocities and the turbulence intensity are strongly affected by wind shear at the region of the blade near wake, with the radial velocity particularly affected. The influence is more obvious as the shear coefficient increases. The effects of wind shear on the axial, tangential, and radial velocities and the turbulence intensity increase as the air flows downstream.