Effect of leading edge geometry on aerodynamic performance of a flat plate

Abstract

Flow separation around flat plate is influenced by the thickness and leading edge geometry, which creates the shear stresses and pressure distribution manifesting into unsteady aerodynamic forces. Leading edge geometries have been widely reported but the influence of leading edge curvature at low Reynolds numbers (Re) have found less attention. The present study uses two dimensional numerical simulation to investigate the effect of a hemispherical curvature (protuberance) at the leading edge and reports how vortex shedding, shedding frequencies and aerodynamic forces are affected over a range of angles of attack ($0^\circ \leq α\leq 25^\circ$) at Re = 1000. Thicker vortical regions are formed near the plate with curvature at the leading edge. Onset of shedding is noted at angle of attack of $5^\circ$ for the plate with curvature at the leading edge and it gets delayed for simple flat plate. The temporal force coefficients on the plates show multiple frequencies at higher angles of attack. The plate with curvature at the leading edge has a glide ratio of 1 at $0^\circ$ angle of attack and has equivalent glide ratio to that of simple flat plate at higher angles of attack. The simple flat plate has better glide ratios at moderate angles of attack like $5^\circ, 10^\circ$ and $15^\circ$. The results will help in making engineering informed design decisions for smaller unmanned aerial/aquatic vehicles cruising at low Reynolds numbers.