Analysis of Ground Effect on a Symmetrical Airfoil

A Detailed Study and Computational Fluid Dynamics investigation was conducted to ascertain and highlight the\ud different ways in which ground effect phenomena are present around a symmetrical aerofoil-NACA 0015- when\ud in close proximity to the ground. The trends in force and flow field behaviour were observed at various ground\ud clearances, for different angle of attack. The analysis was carried out by varying the angle of attack from 00 to\ud 100 and ground clearance of the trailing edge from minimum possible value to one chord length. It was found\ud that high values of pressure coefficient are obtained on the lower surface when the airfoil is close to the ground.\ud This region of high pressure extended almost over the entire lower surface for higher angles of attack. As a\ud result, higher values of lift coefficient are obtained when the airfoil is close to the ground. The flow accelerates\ud over the airfoil due to flow diversion from the lower side and higher mean velocity is observed near the suction\ud peak location. The pressure distribution on the upper surface did not change significantly with ground clearance\ud for higher angles of attack. The lift was found to drop at lower angles of attack at some values of ground\ud clearance due to suction effect on the lower surface as the result of formation of a convergent–divergent passage\ud between the airfoil and the ground plate. The values of drag coefficient were also noted for different ground\ud clearance, which is found to be decreasing as the airfoil is approaching to a closer ground clearance. This ground\ud effect is analyzed using FLUENT 5/6 code