초록 ▼

A method of reducing the effects of induced drag on a foil. A foil is provided with a series of steps along its span in the trailing edge, whereby a series of spaced vortices is generated. The spanwise spacing of the steps is selected so that the vortices are prevented from combining into a larger v

A method of reducing the effects of induced drag on a foil. A foil is provided with a series of steps along its span in the trailing edge, whereby a series of spaced vortices is generated. The spanwise spacing of the steps is selected so that the vortices are prevented from combining into a larger vortex at least until the aerodynamic effect of the larger vortex on the foil is insignificant.

대표청구항 ▼

[ I claim:] [1.] A method of reducing drag on a foil, the foil having a smooth leading edge and a trailing edge, when the foil is moving relative to a fluid, the method comprising splitting flow trailing the foil into a series of at least two vortices spaced along the span of the foil, comprising sp

[ I claim:] [1.] A method of reducing drag on a foil, the foil having a smooth leading edge and a trailing edge, when the foil is moving relative to a fluid, the method comprising splitting flow trailing the foil into a series of at least two vortices spaced along the span of the foil, comprising splitting the flow which leaves the trailing edge of the foil during motion of the foil by providing aerodynamic discontinuities at locations in the trailing edge which are spaced along the span of the foil and which are effective for so splitting flow during all modes of such motion of the foil, so that the vortices, into which the flow that leaves the foil at its trailing edge is split, trail the foil spaced from one another in the spanwise direction relative to the foil during all modes of such motion of the foil, and the vortices formed by the discontinuities remain separate sufficiently aft of the foil to reduce the effect on the foil of induced drag.