A two‐dimensional quantitative parametric investigation of simplified surface imperfections on the aerodynamic characteristics of a NACA 633‐418 airfoil

Emil Krog Kruse,Christian Bak,Niels N Sørensen

doi:10.1002/we.2573

Abstract

AbstractThe aerodynamic performance of a NACA 633‐418 airfoil has been analyzed with disturbances in approximately 1000 different configurations focused on the frontal 10% of the airfoil. The configuration parameters are based on field test samples and rain erosion test specimens. The most important trends are presented by 500 configurations each simulated for 6°, 8°, and 10° angle of attack. The simulations are performed with the DTU Wind Energy in‐house 2D CFD Reynolds‐averaged Navier–Stokes solver, EllipSys2D, combined with the eN transition model for the laminar‐turbulent boundary layer transition. The configurations are modeled by a direct geometrical modification of the airfoil shape. The results show that the most important parameters are the position and the depth/height of the disturbance, with up to 35% lift reduction and 90% lift/drag reduction within the specified angle of attacks and disturbance parameter ranges.

Highlights

The global ambition for increasing renewable energy has led to a high demand for wind turbines
The performance of a wind turbine blade is most sensitive to roughness close to the leading edge of the airfoil,[3,4] giving basis for the general term leading edge roughness (LER)
The focus of this paper is to investigate the important parameters of the shape and extension of LER

Summary

Introduction

The global ambition for increasing renewable energy has led to a high demand for wind turbines. With an objective of performance and optimization, one critical part of a wind turbine are the blades. If a wind turbine blade deviates from the design shape, the result might be reduced power production.[1,2] A deviation in shape can origin from the production imperfections, wear, and tear or surface contamination such as ice or dirt. These factors are often mentioned in the literature and industry as erosion or roughness, with roughness being a more general term. The performance of a wind turbine blade is most sensitive to roughness close to the leading edge of the airfoil,[3,4] giving basis for the general term leading edge roughness (LER)

Methods

Results

Conclusion