Aircraft wing with system establishing a laminar boundary layer flow
For establishment of a laminar attachment line flow, an aircraft wing includes a leading edge including an attachment line, where air impinging on the region flows in a boundary layer spanwise along the leading edge. The leading edge and the attachment line are at least partially formed at first and second slats. The second slat is located adjacent to the first slat in the downstream direction of the attachment line flow, so that the leading edge includes a slat-to-slat junction, where a slat cavity is formed. A duct has a duct entrance at the slat-to-slat junction for receiving spanwise flow along the leading edge of the wing. The duct entrance extends around the leading edge and over the range of positions of the attachment line at the slat-to-slat junction.
1. An aircraft wing comprising: a leading edge, the leading edge including an attachment line being a region where air impinging on the region flows in a boundary layer spanwise along the leading edge; a first slat and a second slat, wherein the leading edge and the attachment line are at least partially formed at the first and second slats, and wherein the second slat is located adjacent to the first slat in a downstream direction of attachment line flow, so that the leading edge includes a slat-to-slat junction; wherein a slat cavity formed at the slat-to-slat junction beneath a skin area of at least one of the first and the second slats; and a duct having a duct entrance at the slat-to-slat junction configured to receive spanwise flow along the leading edge of the wing, the duct being at least partly formed by said slat cavity, wherein the duct entrance extends around the leading edge and over a range of positions of the attachment line at the slat-to-slat junction, wherein the second slat includes a slat lip extending from the slat-to-slat junction transverse to the leading edge, protruding in a chordwise direction over an adjacent slat lip area of the first slat so that a step is formed between the first and second slats, wherein said duct entrance comprises an orifice in said step.
2. The aircraft wing according to claim 1 , wherein said slat lip area of the first slat comprises an indentation configured to form said step and said orifice is formed between said indentation and said slat lip of the second slat.
3. The aircraft wing according to claim 1 , wherein the first and second slats each includes leading edge lines, wherein said leading edge lines are offset to each other in a chordwise direction when seen in a thickness direction of the wing configured to form said step in the slat-to-slat-junction.
4. The aircraft wing according to claim 1 , wherein said first and second slats are movable relative to each other, and wherein the slat lip of the second slat is movable relative to the lip area of the first slat in the chordwise direction in order to change an entrance area of said orifice.
5. The aircraft wing according to claim 1 , wherein said duct comprises a duct exit formed at a slat lower surface trailing edge.
6. The aircraft wing according to claim 1 , wherein said duct entrance comprises a slot in a leading edge skin surface of the second slat at the slat-to-slat junction, wherein the slot communicates with the slat cavity and extends in a wing thickness direction.
7. The aircraft wing according to claim 1 , wherein the duct is configured as a passive boundary layer flow influencing device such that, during flight, an air pressure lower than an air pressure at the leading edge is established within the duct so that air is drawn through the duct entrance without use of an additional suction or pump mechanism.