Note on the Lift acting On a Circular-arc Aerofoil in a Stream bounded by a Plane Wall

Being a continuation of the preceding paper, Green's new method, somewhat extended by the present writer, is applied to the evaluation of the lift acting on a circular-arc aerofoil in the presence of an infinite plane rigid wall. The expression for the lift is obtained in the form of a power series. By performing detailed numerical calculations, a discussion is made on the manner in which the ground-effect on the lift of an aerofoil is modified by its camber. It is thus found that in accordance with the prediction made by Tomotika et al. , as the arc-aerofoil of sufficiently small camber approaches the wall, the lift first decreases and then tends to increase to values which are greater than the corresponding values for the same arc-aerofoil in an unlimited stream, especially when the angle of attack takes small values as used in practice. It is also found that the rate of increase in the lift becomes smaller as the camber of the aerofoil increases.