Experiments on the reduction of base drag of a blunt trailing edge aerofoil in subsonic flow

Abstract

It has been pointed out by a number of investigators that aerofoils with blunt trailing edges have many advantages, both structural and aerodynamic, at transonic and supersonic speeds. However, a profile with a blunt trailing edge unfortunately creates a high base drag at subsonic speeds and this could result in the total drag being considerably higher than that for a profile with a sharp trailing edge. This base drag arises due to the periodic vortex shedding from the blunt base which causes low pressures in the wake thus creating the base drag.In order to reduce the base drag of a blunt trailing edge at subsonic speeds, this periodic vortex shedding must be suppressed. This has been achieved by various methods — a splitter plate behind the base, the base bleed, base cavities — and these have shown varying degrees of drag reduction.