Patent ID: 6151883
Filing Date: 2000-11-28
Classification: F02K,F15D,Y02T

Abstract:
An aircraft propulsive power unit comprising an efflux duct in which gaseous fluid is conducted in a predetermined first flow direction for discharge from an exit end of the duct in the production of forward thrust, and a thrust reversing arrangement for diverting gaseous fluid in the duct or gaseous fluid discharging from the exit end of the duct to redirect the flow from the first flow direction to a second flow direction to produce reverse thrust, the reversing arrangement having a flow redirecting structure comprising a redirecting downstream wall against which fluid flow impinges in the first flow direction and an upstream wall having a leading edge, the upstream wall round which the fluid flow turns and which has a boundary surface so formed as to support adherence of a boundary layer of the redirected fluid flow at the boundary surface, wherein the upstream wall so extends away from the efflux duct as to provide a continuous convex-shaped curved boundary surface of such curvature over at least a part of the wall as to support adherence of the boundary layer of the redirected fluid flow, and wherein the curved boundary surface is selectively disrupted to generate vortices in the boundary layer to prevent or delay boundary layer separation, and wherein the upstream wall is formed or provided with projecting elements which project from the boundary surface at a location in the region of the leading edge of the boundary surface to generate the vortices in the boundary layer.