An experimental and numerical two-dimensional analysis of the effect of a rotating cylinder on an inverted aerofoil in ground effect

A Two-Dimensional experimental and numerical analysis has been conducted to determine the effect that the front wheel of an open wheel racing car would have on the front wing. Previously published experimental and numerical analysis has concentrated on individual aerodynamic components of an open wheel race car, or on explaining the contribution that these components make to a race vehicle’s aerodynamic performance. In this study, Laser Doppler Anemometry (LDA) and Flow Visualization experiments were conducted to gain insight into the flow. An inverted NACA4412 aerofoil was used to represent the front wing, while a circular-cylinder, of diameter equal to the chord of the aerofoil, was used to represent the wheel. Additionally a moving ground was utilised to replicate in the wind tunnel the ground condition experienced by a racing car. From the experimental analysis it was determined that the inverted aerofoil in ground effect experienced separation from the bottom surface at much larger angles of attack in comparison to what the aerofoil would experience on its own. It is believed that the high pressure region generated by the cylinder contact patch delayed separation from occurring on the bottom side of the aerofoil. Additionally it was found that at some angles of attack, the aerofoil would experience separation on both the top and bottom sides. LDA results obtained during this investigation have also been used to verify a 2D CFD model of the same problem.