Aerodynamic characteristics of variously modified leading-edge protuberanced (LEP) wind turbine blades under various turbulent intensities

Abstract

A series of wind tunnel tests were performed to investigate the effect of turbulent inflows on the aerodynamic characteristics of variously modified leading-edge protuberanced (LEP) wing configurations at various turbulence intensities. A self-developed passive grid made of parallel arrays of round bars was placed at different locations of the wind tunnel to generate desired turbulence intensity. The aerodynamic forces acting over the baseline straight leading-edge model and the modified small, medium and high LEP wing configurations were obtained from the surface pressure measurements made over the wing at different turbulence intensities using MPS4264 Scanivalve simultaneous pressure scanner corresponding to a sampling frequency of 700Hz. All the test models were tested for a wide range of angles of attack ranging between −45° ≤ α ​≤ ​45° at turbulence intensities varying between 0.51% ​≤ ​TI ​≤ ​4.92%. Results reveal that the time-averaged mean coefficient of lift (CL) increases with the increase in the turbulence intensity associated with smooth stall characteristics rendering the modified LEP test models advantageous. Furthermore, based on the surface pressure coefficients the underlying dynamics behind the stall delay tendency were discussed. Additionally, attempts were made to statistically quantify the aerodynamic forces using standard deviation at both the pre-stall and the post-stall angles.