On the Characteristics of Wing with Tip Clearance : Part 3, The Force Acting on a Rectangular Wing of Low Aspect Ratio

抄録

The effect of the tip clearance on the aerodynamic force is investigated theoretically about wings in an inviscid, incompressible, uniform flow. The present investigation is carried out by extending Bollay's analysis which was made along the lines suggested by Prandtl. From the author's experiments it is shown that Bollay's simplifying assumptions are also applied to the wing with the tip clearance. The assumptions are as follows: (1) the vortex strength is constant across the span, (2) the downwash along the span is constant and equal to the value at the center of the span. Bollay's method for evaluating integrals, however, can not be applied to calculate the induced velocities due to the vortex system formed by mirror images of the wing. The author makes clear successfully those integrals and obtains the force acting on the wing. The agreement in a force perpendicular to the wing surface between the present theory and the author's experiment for the wing of aspect ratio 1.43 is good for a small tip clearance and fair for a large one.