A Numerical Study on the Unsteady Aerodynamic Characteristics of Thick Aerofoils with Wavy LeadingEdges

摘要

Numerical simulations are performed over a Wavy Leading Edge (WLE) aerofoil using aNACA0021 section with a WLE wavelength of 11% and an WLE amplitude of 3% of themean chord. The results obtained match the experimental data available in literature withbetter accuracy than previous publications. Nevertheless it is observed that, in contrastto what has been shown in previous literature the flow over a WLE is not periodic inevery wavelength when the angle of attack is very high. Instead Laminar SeparationBubbles (LSB) appear at every second trough that eventually transition to turbulenceand enables partial reattachment for a small percentage of the chord length. On the othertroughs however, the flow suffers from laminar separation at the leading edge. It is alsofound out that the regions with the LSBs give an increased aerodynamic efficiency withrespect the other trough sections of roughly 6% for the tested WLE parameters at angle of attack of 20 ? . Furthermore the WLE are able to debilitate the strength of the vortexshedding mechanism because of the heterogeneity that promote to the flow across thespan.