EP0244334A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Airfoil-shaped body
Assignee: RTX Corp
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Filing: 1987-04-07
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Granted: —
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Expires: 2007-04-07
Abstract
Abstract An airfoil-shaped body (30) has a relatively thin trailing edge with a series of alternating, adjoining, downstream extending troughs (32) and ridges (34) in its suction surface (36) which form wave-like surface undulations terminating at the trailing edge. The ridges (34) in the suction surface (36) form corresponding troughs (38) in the pressure surface (42) near the trailing edge; and the troughs (32) in the suction surface (36) form corresponding ridges (40)near the trailing edge of the pressure surface (42). The resulting airfoil-shaped body (30) has a trailing edge with a wave-like shape. The trough and ridge construction delays or prevents two-dimensional boundary layer separation without creating an undesirable drag penalty.
Inventors
- 👤 Walter M. Presz, Jr.
- 👤 Robert W. Paterson
- 👤 Michael R. Werle
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-25 08:20
CPC Classifications
B; B64; B64C; B64C21/00; B64C21/10; Y; Y02; Y02T; Y02T50/00; Y02T50/10
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
113 words
An article adapted to be disposed in a fluid which moves downstream relative to the article, the article comprising a first surface and a second surface spaced apart and defining an airfoil shaped body having a thin trailing edge, said body having a downstream portion terminating at said trailing edge, said downstream portion being shaped to define alternating ridges and troughs in both said first and second surfaces, the troughs in each such surface defining the ridges in the other of such surfaces at least along said trailing edge, each of said ridges and troughs extending generally along the streamlines of the bulk fluid flow adjacent the surface of such ridge or trough.
Claim 2
Dependent Claim
113 words
An article adapted to be disposed in a fluid which moves downstream relative to the article, the article comprising a first surface and a second surface spaced apart and defining an airfoil shaped body having a thin trailing edge, said body having a downstream portion terminating at said trailing edge, said downstream portion being shaped to define alternating ridges and troughs in both said first and second surfaces, the troughs in each such surface defining the ridges in the other of such surfaces at least along said trailing edge, each of said ridges and troughs extending generally along the streamlines of the bulk fluid flow adjacent the surface of such ridge or trough.
Claim 3
Dependent Claim
60 words
The article according to claim 1, wherein the depth of said troughs and height of said peaks is substantially zero at their upstream ends, and the sum of said depth of one of said troughs and height of an adjacent peak at said trailing edge is at least twice the 99% boundary layer thickness measured immediately upstream of said troughs.
Claim 4
Dependent Claim
189 words
In an airfoil shaped body having a nominal cross sectional shape, a thin trailing edge and a suction surface terminating at said trailing edge, and adapted to be disposed in a fluid moving downstream relative thereto at a selected operating angle of attack A to produce high loading at which a separation region on said suction surface would be expected to occur for such nominal shape, such separation region initiating along a separation line located upstream from said trailing edge, means for preventing such separation from occurring on said suction surface at such angle of attack comprising a plurality of alternating, adjacent troughs and ridges in said suction surface extending from upstream of said expected separation line and extending generally along the streamlines of the bulk fluid flow adjacent to the suction surface, wherein the sum of the depth and height of an adjacent troughs and ridge is substantially zero at their upstream ends, and the sum of the depth of one of said troughs and height of an adjacent ridge at said trailing edge is at least what the thickness of the eliminated separation region would have been.
Claim 5
Dependent Claim
189 words
In an airfoil shaped body having a nominal cross sectional shape, a thin trailing edge and a suction surface terminating at said trailing edge, and adapted to be disposed in a fluid moving downstream relative thereto at a selected operating angle of attack A to produce high loading at which a separation region on said suction surface would be expected to occur for such nominal shape, such separation region initiating along a separation line located upstream from said trailing edge, means for preventing such separation from occurring on said suction surface at such angle of attack comprising a plurality of alternating, adjacent troughs and ridges in said suction surface extending from upstream of said expected separation line and extending generally along the streamlines of the bulk fluid flow adjacent to the suction surface, wherein the sum of the depth and height of an adjacent troughs and ridge is substantially zero at their upstream ends, and the sum of the depth of one of said troughs and height of an adjacent ridge at said trailing edge is at least what the thickness of the eliminated separation region would have been.
Claim 6
Dependent Claim
44 words
The airfoil shaped body according to claim 3, including a pressure surface terminating at said thin trailing edge, wherein said troughs and ridges in said suction surface form, respectively, ridges and troughs, in said pressure surface, and said thin trailing edge is wave shaped.
Claim 7
Dependent Claim
19 words
The airfoil shaped body according to claim 4, wherein said troughs and ridges form an undulating, smooth suction surface.
Claim 8
Dependent Claim
69 words
The airfoil shaped body according to claim 4, wherein said troughs and ridges are generally "U" shaped in cross section perpendicular to their length, said trough surfaces blending smoothly with adjacent ridge surfaces, changes in trough depth and ridge height occurring smoothly, the trough contour and size along its length being selected such that streamwise two-dimensional boundary layer separation on the surface of the troughs and ridges is eliminated.
Claim 9
Dependent Claim
43 words
The airfoil shaped body according to claim 4, wherein the sum of the depth of one of said troughs and height of an adjacent ridge at said trailing edge is about twice what the thickness of the eliminated separation region would have been.
Claim 10
Dependent Claim
20 words
The airfoil shaped body according to claim 4 or 6, wherein said body is a gas turbine engine stator vane.
Claim 11
Dependent Claim
20 words
The airfoil shaped body according to claim 4 or 6, wherein said body is a gas turbine engine rotor blade.
Claim 12
Dependent Claim
18 words
The airfoil shaped body according to claim 1, wherein said body is a sail for a sailing vessel.
Claim 13
Dependent Claim
40 words
The airfoil shaped body according to claim 4 or 6, wherein at the trailing edge the distance between adjacent ridge peaks is between 0.5 and 4.0 times the sum of the depth and height of an adjacent trough and ridge.
Claim 14
Dependent Claim
40 words
The airfoil shaped body according to claim 4 or 6, wherein at the trailing edge the distance between adjacent ridge peaks is between 0.5 and 2.0 times the sum of the depth and height of an adjacent trough and ridge.
Claim 15
Dependent Claim
32 words
The airfoil shaped body according to claim 3, wherein said troughs in said suction surface each include side walls which converge as they approach the trailing edge to accelerate the flow therein.
Claim 16
Dependent Claim
27 words
The airfoil shaped body according to claim 3, wherein the thickness of said body decreases toward said trailing edge along the length of said troughs and ridges.
Claim 17
Dependent Claim
61 words
A sail for a sailing vessel, said sail, in its raised position, adapted to define an airfoil having a pressure and suction surface and a trailing edge, said trailing edge having a wave-shape forming a plurality of alternating ridges and troughs in both sides of said sail along a region of said sail immediately upstream of and including said trailing edge.
Claim 18
Dependent Claim
61 words
A sail for a sailing vessel, said sail, in its raised position, adapted to define an airfoil having a pressure and suction surface and a trailing edge, said trailing edge having a wave-shape forming a plurality of alternating ridges and troughs in both sides of said sail along a region of said sail immediately upstream of and including said trailing edge.
References Cited (Backward Citations)
No citation records indexed.
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