Flow Field Phenomena about Lift and Downforce Generating Cambered Aerofoils in Ground Effect

Abstract

A Computational Fluid Dynamics investigation was conducted to ascertain and highlight the different ways in which ground effect phenomena are present around both an upright (lift generating) and inverted (downforce generating) cambered aerofoil when in close proximity to the ground. The trends in force and flow field behaviour were observed at various ground clearances, while the angle of attack was held constant at 6 degrees. The different mechanisms by which ground effect influences the two different configurations were highlighted through observation of the pressure coefficient plots, contour maps of velocity and turbulence intensity and their effect on the normal and drag forces. The primary contributing factor to the increase in normal force for the lifting aerofoil, as the ground was approached, was a constriction and rise in pressure of the flow. For the downforce aerofoil, a significantly sped up flow increased suction and enhanced downforce. Also discussed is the observation of a reduction in lift for the upright aerofoil as its ground clearance is reduced through high and medium clearances.