Wind tunnel tests for vortex generators mitigating leading-edge roughness on a 30% thick airfoil

Abstract

In this study, the aerodynamic performance of a thick airfoil is analysed, after installing leading-edge roughness to emulate a severe state on the airfoil surface. The impact on aerodynamic coefficients has been quantified using two roughness methods: zig-zag tape and sandpaper. Wind tunnel tests are carried out at a Reynolds number of 3•106. At low angles of attack, zig-zag tape and sandpaper provide comparable lift and drag coefficients but significant variations of these coefficients are obtained for high angles of attack. Stalled flow is the cause of the most significant variation on the airfoil performance between smooth and rough surface states. Vortex generators are adapted to recover the lift coefficient value previously given by the airfoil under smooth conditions. As a result, vortex generators are able to reduce the loss of lift and the sensitivity of the airfoil to the rough state.

Impact of high size distributed roughness elements on wind turbine performance

“…Recently more research has been performed in this field. Bak [6] studied the influence of the wind characteristics on the power production loss due to the existence of imperfections on the airfoil surface, Maniaci et al [7] focused their studies on reducing the uncertainties and [8] et al worked on the definition of mitigation measures to reduce the harmful effect of roughness.…”

Study on k−ω−Shear Stress Transport Corrections Applied to Airfoil Leading-Edge Roughness Under RANS Framework

“…The studied airfoil is property of Nordex Energy Spain S.A.U. Experiments from Guti errez et al [10] are taken to validate the test case.…”

“…As a result, flow separation occurs downstream of the roughness elements. Guti errez et al [10] measured this flow separation on the pressure side of a 30% thick airfoil.…”

“…However, a wide range of AEP loss can be found in the literature. The sensitivity of the empirical [10] and computational methods [8] justifies the difference in AEP estimation.…”

Leading edge topography of blades–a critical review

“…The computational fluid dynamics (CFD) method is one of the most widely used wind turbine blade simulation methods to accurately predict the boundary layer and various unsteady flow characteristics resulting from blade leading edge roughness [145][146][147][148]. The experiments were conducted mainly using a pre-designed model of the damaged wing installed in a wind tunnel, where the leading edge damages were simulated based on the measurements of ex-serviced turbine blades [149,150]. In particular, Pires conducted more practical tests in the field to further advance the understanding and modelling of blade surface roughness effects [151].…”