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An Increase in jet penetration due to the wall boundary layer is determined in the flow field including an aerodynamic interference between the wall boundary layer and the jet. The aerodynamic effect of the wall boundary layer is replaced by that of a secondary vortex filament resulting from vorticity in the wall boundary layer. A differential equation governing the increase in jet penetration is derived using the circulation around the secondary vortex filaments, its induced velocity and the empirical decay law of the jet axial velocity along the jet centerline. The circulation around the secondary vortex filament is estimated according to Hawthorne's theory (1)* and expressed in terms of aerodynamic characteristics of the wall boundary layer. A numerical example of the present analysis shows a fairly good agreement with the experiment. This indicates that the used vortex flow model simulates the real flow conditions well.

The aerodynamic characteristics around a wing tip are investigated with a first order panel method. The geometry chosen for the study is a rectangular wing of aspect ratio 8.43,with RAF6 airfoil of 10% thickness ratio. The panel method gives similar aerodynamic characteristics to experimental ones even near the tip, such as a dominant suction pressure distribution present near the trailing edge around the tip, and the increase in the local lift and drag at the very narrow region of the tip. These properties are caused by the strong spanwise velocity component around the wing tip, the inviscid effects of which are described in detail, with respect to pressure coefficient, local lift and drag coefficients, downwash, and vorticity on the wing.