DE102005012575B4 - Aerodynamic component that generates an up or down drive with a sawtooth-shaped course of its trailing edge - Google Patents

Abstract

An aerodynamic component (4) which generates an up or down drive and which ends downstream with a trailing edge (11) having a sawtooth course with a plurality of saw teeth (10), each saw tooth (10) of the sawtooth course of the trailing edge (10). 11), viewed opposite to the direction of flow (17), has a shorter section (12) extending predominantly parallel to the direction of lift (5) or downforce and a longer section (13) adjoining thereto, characterized in that the longer section (13 ) extends predominantly parallel to a main extension direction of the trailing edge (11) and that an upper side (9) and a lower side (10) of the component (4) starting from the sawtooth-shaped trailing edge (11) have a sawtooth-shaped profiling which opposes the direction of flow (17) extends over at least 20% up to 65% of a tread depth of the component (4).

Description

The invention relates to an aerodynamic component, in particular an airfoil of an aircraft, which generates an up or down drive at the flow, which ends downstream with a trailing edge and having the further features of the preamble of claim 1.

An airfoil of an aircraft, in particular a commercial aircraft, generates a buoyancy. The fins of a horizontal stabilizer of an aircraft, to which the invention is also applicable, in contrast, often produce an output. The physical processes on the respective aerodynamic component differ in generating an input or output only in the direction of the generated force, the direction of a lateral deflection of the flow and the direction of rotation resulting therefrom, As far as the invention will be described below with reference to a wing , These versions can be transferred to an output generating aerodynamic component taking into account the reversed sign reversal.

STATE OF THE ART

The buoyancy of a wing is directly proportional to a circulation of air around the wing in the direction normal to its flow. According to Helmholtz, this circulation is equal to the summed up vortices of the shear layers floating down at the trailing edges of the wing and the wing tips. These shearing layers wind at an icy distance behind the aircraft to one or more pairs of vertebrae and thereby form a vortex system with a relatively small contact surface between the moving and the stationary air mass. A dissipation of turbulent energy from the vortex system into the free flow surrounding the vortex system is thereby fundamentally impeded.

An aerodynamic component, in particular a wing of an aircraft, with the features of the preamble of claim 1 is known from US 5 088 665 A known. Here are either in the direction of the flow extending sawtooth projections attached to the trailing edge of the aerodynamic component, which can extend to the trailing edge and there lead to a local thickening of the profile of the aerodynamic component, or the trailing edge of the aerodynamic component is in the direction cut in sawtooth shape of the flow. The attached to the trailing sawtooth projections can also be folded down around the trailing edge, so that they are employed against the flow.

From the EP 1 112 928 A2 is known a wing profile, on which form a suction side and a pressure side in flow through a fluid and having a divergent thickened or angled trailing edge. Concretely, the angling of the trailing edge can be designed in the manner of a Gurney flap. The divergent thickened or angled trailing edge is provided on the suction side and / or the pressure side with means for disturbing a periodic flow separation and / or for flow stabilization. As means for the pressure side are thereby arranged on the pressure side in front of the trailing edge or up to extending incisions or lands to the pressure side and / or away from the trailing edge extending individual elements, perforations of the angled, in the horizontal direction on the pressure side and at the same time horizontally extending sawtooth or wave-shaped elements proposed, which may be perpendicular or at an angle obliquely to the pressure side facing individual elements. As a means for the suction side arranged or up to there extending elements or webs are proposed in front of the trailing edge, which preferably have the shape of a triangle, trapezoid or a wave in cross section.

OBJECT OF THE INVENTION

The invention has for its object to avoid far-reaching wake turbulence behind flying, especially taking off and landing aircraft by the combination of individual vortexes to vortex systems with high energy density on the up or down-generating aerodynamic components of the aircraft is originally prevented.

SOLUTION

The object of the invention is achieved by an aerodynamic component having the features of patent claim 1. Preferred embodiments of the new aerodynamic component are described in the dependent claims 2 to 8. Claim 9 relates to an aircraft with at least one aerodynamic component according to one of claims 1 to 8.

DESCRIPTION OF THE INVENTION

The new aerodynamic component has a trailing edge, which has a sawtooth-shaped course when viewed against the direction of the flow. The term "sawtooth course" should be understood to mean that the course of the trailing edge describes several saw teeth. Each sawtooth is defined as having a shorter portion extending predominantly parallel to the direction of up or down and one adjoining it has subsequent longer extending predominantly parallel to a main extension direction of the trailing edge section. The longer section is then followed by a shorter section of the next sawtooth, and so on.

Due to the sawtooth profile of the trailing edge of the aerodynamic component, in the region of each sawtooth, the shear layers of the flow are reversed from the two sides of the aerodynamic component, i. h., the flow from the top of the aerodynamic component is directed below the flow from the bottom of the aerodynamic component. The relative displacement of the flows required for this purpose is brought about by the shorter section of each saw tooth extending predominantly parallel to the direction of the up or down drive. Due to the reversal of the shear layers in the area of the saw teeth due to the rearrangement of the flow parallel to the direction of the up or down, there are vortices which have a reverse direction of rotation relative to a vortex at a free end of the aerodynamic component, ie typically a vortex at a wing tip and thus preventing the shearing of the trailing edge from floating down shear layers only to vortices that can easily unite with the same direction of rotation vane at the free end of the aerodynamic component. In the region of each saw tooth of the trailing edge, two counter-rotating vortices are created, and these vortices of different rotational direction of all the saw teeth form an outer area around the vortices that detach from the free end of the aerodynamic component. This outer area can not unite with the vortex in the core, and is unstable, so that its energy share dissipates quickly.

As a result of the up or down, transverse movements of the flows that occur in the boundary layers of the flows on the aerodynamic component arise. In order to take advantage of these in the rearrangement of the flows at the trailing edge of the aerodynamic component particularly well, with each saw tooth, as far as it is considered in the main extension direction of the trailing edge to a free end of the aerodynamic component, the shorter section predominantly opposite to the direction of the aerodynamic component or output drive, while the longer portion has a flat slope in the direction of the up or down drive. In a lift generating wing, the flow lines in the shear surface at the top of the wing are curved away from the wing tip while curved toward the wing tip at the bottom of the wing. The course of the saw teeth defined here for this case corresponds to a flat rise to the wing tip and a subsequent sharp drop in the trailing edge. As a result, the flow at the bottom of the wing in the region of each sawtooth to the outside, d. H. towards the wing tip, and steered up, while simultaneously directing the flow at the top of the wing inward and downward.

Where, as for example in the vicinity of a buoyancy-generating landing flap on a wing, the circulation towards the free end of a lift-generating aerodynamic component increases and does not decrease as normal, d. H. the curvature of the flow lines at the top of the component towards the free end and at the bottom of the component away from its free end, the course of the saw teeth is also reverse, so that the trailing edge drops flat to the free end and rises sharply.

For each saw tooth, the shorter portion may have an inclination away from the free end of the aerodynamic component as viewed from the trailing edge of the trailing edge to the free end of the aerodynamic component. This means that the saw teeth of the trailing edge are undercut. As a result, in the region of each sawtooth, the flow from the one side is guided further below the flow from the other side of the aerodynamic component.

For each sawtooth, the longer section in the main trailing edge direction of the trailing edge may be 1.4 - (= square root of 2) up to 20 times longer than the shorter section in the direction of up or down. The widths of the saw teeth, which correspond to the longer sections in the main extension direction of the trailing edge, should preferably be adjusted so that a change in the circulation distribution between the individual saw teeth over the span, d. H. the main extension of the trailing edge is as constant as possible. This corresponds to the requirement that approximately equal swirls occur at all saw teeth, each having an opposite direction of rotation to a vortex at the free end of the aerodynamic component. In addition, all of the saw teeth generate vortices with the same direction of rotation as the vortices at the free end of the aerodynamic component, which are each slightly stronger than the vortices with the opposite direction of rotation.

The height of the saw teeth, which corresponds to the shorter sections in the direction of the up or down drive, is to be selected as a function of the thicknesses of the boundary layers of the flows at the trailing edge of the aerodynamic component. The height of each sawtooth should be about the same order of magnitude as the sum of the thicknesses of the boundary layers on each side of the aerodynamic component, that is about 100 to 300% of the thickness of one of the boundary layers of the flows in that region of the trailing edge Reassign currents on both sides of the component. Considering a wing of a modern airliner where the wings are set at an effective angle of 10.5 °, taking into account the 99% criterion, the thickness of the boundary layer at the trailing edge of the wing is approximately 1 dm. Accordingly, the height of the saw teeth should be about 2 dm. The favorable actual heights of the saw teeth depend on the conditions of the individual case. However, they will typically be in a range of 50 to 300 mm.

It is understood that not only the trailing edge of the aerodynamic component has a sawtooth-shaped course, but that the aerodynamic component from the trailing edge over a substantial part of its tread depth will have a sawtooth-shaped profiling. Specifically, the profiling of the aerodynamic component will typically extend over at least 20% of the tread depth of the component against the direction of flow from the trailing edge. The profiling may also extend over up to 65% of the tread depth. However, it typically does not extend to the area of the largest profile thickness of the aerodynamic component.

The profile edges of the profiling of the aerodynamic component should follow the transverse movements of the flows in the boundary layers on the surfaces of the aerodynamic component in order to avoid creating undesired additional vortices. For this purpose, the profile edges of the profiling on the pointing in the direction of the up or down side of the aerodynamic component viewed in the direction of the flow can be curved away from a free end of the aerodynamic component, while the profile edges of the profiling on the contrary to the direction of up or Viewing side of the aerodynamic component viewed in the direction of the flow are curved towards the free end of the aerodynamic component. In the case of a wing of an aircraft, the tread edges are thus viewed inwardly at the top in the direction of flow, d. H. Curved away from the wing tip, while the profile edges are curved at the bottom to the outside.

A deviation from the normal circulation of the circulation distribution, which can occur, for example, in a buoyancy-generating landing flap and which leads to a different curvature of the flow lines (see above), must be taken into account in the curvature of the profile edges.

In particular, in the case of an aircraft, the wings may have the sawtooth-shaped trailing edge according to the invention. Likewise, however, horizontal stabilizers can be provided with such a sawtooth-shaped trailing edge. If these elevators essentially produce a downforce, their trailing edges should have a reverse pitch pattern as the trailing edges of the wings.

It may be advantageous if the aerodynamic component has the sawtooth-shaped trailing edge only in certain operating situations. For example, the trailing edge of the wing of an aircraft can only be sawtoothed when it launches or lands, with the wake vortices trailing behind it of particular interest. A temporary sawtooth trailing edge may be provided by actuators that deform the aerodynamic component, or by elements extendable from the non-serrated trailing edge of the component, such as an airfoil of an airfoil having the sawtooth trailing edge.

Advantageous developments of the invention will become apparent from the dependent claims and the entire description. Further features are the drawings - in particular the illustrated geometries and the relative dimensions of several components to each other and their relative arrangement and operative connection - refer. The combination of features of different embodiments of the invention or features of different claims differing from the chosen relationships is also possible and is hereby stimulated. This also applies to those features which are shown in separate drawing figures or are mentioned in their description. These features can also be combined with features of different claims.

BRIEF DESCRIPTION OF THE FIGURES

In the following the invention will be further explained and described with reference to a preferred embodiment.

1 shows a portion of a wing trailing edge of a wing of a commercial aircraft; and

2 shows a view of the wing according to 1 from above.

DESCRIPTION OF THE FIGURES

The in the 1 and 2 partially reproduced wings 1 a commercial aircraft 2 , otherwise only the contour of his trunk 3 is indicated, is shown greatly simplified and serves as an example of an aerodynamic component 4 for generating an upward buoyancy 5 , The size of the buoyancy 5 extending over the entire span of the wing 1 from the hull 3 Distributed away, is proportional to a circulation around the wing 1 in the drawing plane of 1 , Ie. it inevitably creates vortex 6 . 7 and 19 that make up behind the airliner 2 forms a wake. The invention relates to a measure, the vortex system of the wake behind the airliner 2 to keep as unstable as possible in order to dissipate the energy present in the vortex system over the shortest possible distance behind the airliner.

The in 1 right vortex drawn vortex 6 should represent the wing tip vertebra, located at the wing tip of the wing, not shown here 1 trains and in 1 has a direction of rotation counterclockwise. It is based on a transverse movement of flows of boundary layers on the wing 1 at the bottom 8th of the wing 1 from the hull 3 away and at the top 9 of the wing 1 to the hull 3 run out. The vortex 7 however, stands for a vortex, which is at the wing 1 on every saw tooth 10 a sawtooth course of a trailing edge 11 of the wing 1 is produced. In the area of each sawtooth 10 falls the trailing edge 11 in its main extension direction from the hull 3 looked away in a section 12 steep. In the area of the section 12 is the trailing edge 11 even undercut, ie it runs slightly to the hull 3 back. On both sides of the section 12 border longer sections 13 the trailing edge 11 in which it rises flat to the waste in the area of the sections 12 compensate again. The ratio of the heights of the saw teeth 10 that the sections 12 match, at their latitudes, the sections 13 is approximately 1: 6. The height of the saw teeth 10 is tuned so that an energetic part of the flow around the wing 1 on the bottom 8th in the area behind each section 12 the trailing edge 11 over a high-energy part of the flow at the top 9 of the wing 1 to be led. This is at the in 1 right and left saw teeth 10 through arrows 14 and 15 indicated. The transverse direction of the arrows 14 and 15 is based on the transverse components of the currents around the wing 1 that was previously mentioned and also cause the vortex 6 at the wing tip of the wing 1 is. In the area of each section 12 the trailing edge 11 lead the transverse components of the currents around the wing 1 according to the arrows 14 and 15 because of the rearrangement of the flows parallel to the direction of buoyancy 15 to that the vortex 7 an opposite direction of rotation to the vortex 6 exhibit. In the areas of the sections 13 the trailing edge 11 however, the transverse components of the flows result in vortices 19 with the same direction of rotation as the vortex 6 ,

2 covering the entire wing 1 up to its wing tip 16 in a view from above, illustrating that not only the trailing edge 11 having the sawtooth shape, but that of the trailing edge 11 starting also the top 9 of the wing 1 and accordingly its underside not visible here 8th are sawtooth profiled. The profiling extends from the trailing edge 11 against the direction of the flow 17 of the wing 1 over about 50% of its tread depth. profile edges 18 the profiling of the top 9 of the wing 1 point in the direction of the flow 17 looks at you to the hull 3 curved course on. Hereby they take the transverse component of the flow in the boundary layer at the top 9 of the wing 1 on that with the arrow 15 is highlighted. The profile edges of the corresponding profiling of the wing 1 on its underside, in contrast to the wing tip 16 Curved to the there to the wingtip 16 pointing transverse component in the boundary layer to follow, with the arrow 14 is indicated.

The rearrangement of the shear surfaces in the area of the sections 12 the saw teeth 10 the trailing edge 11 of the wing 1 causes the ones at the trailing edge 11 floating boundary layers, though together with the inevitable vortex 6 at the wingtip 16 of the wing to a main vortex with high energy density roll up, from which the energy due to the different directions of rotation of the rolled up vortex 7 and 19 is dissipated faster, at least in the outdoor areas. The formation of opposing vortices 7 due to the rearrangement of the shear surfaces prevents the formation of a concentrated exclusively uniformly rotating main vortex. At the convergence of the vortex 6 . 7 and 19 behind the airliner 2 the resulting vortex system has an outer area of the mutually opposing vertebrae 7 and 19 Therefore, it is already less stable from the outset, so that the energy present in it is dissipated more quickly.

LIST OF REFERENCE NUMBERS

1

Hydrofoil

2

airliner

3

hull

4

component

5

boost

6

whirl

7

whirl

8th

bottom

9

top

10

sawtooth

11

trailing edge

12

section

13

section

14

arrow

15

arrow

16

pinion

17

inflow

18

profile edge

19

whirl

Claims (9)

Aerodynamic component ( 4 ), which generates an up or down drive on the flow and the downstream with a trailing edge ( 11 ), which has a sawtooth profile with several saw teeth ( 10 ), each saw tooth ( 10 ) of the sawtooth course of the trailing edge ( 11 ) against the direction of the flow ( 17 ) considers a shorter, predominantly parallel to the direction of buoyancy ( 5 ) or downdraft section (FIG. 12 ) and a subsequent longer section ( 13 ), characterized in that the longer section ( 13 ) predominantly parallel to a main extension direction of the trailing edge ( 11 ) and that a top side ( 9 ) and a bottom ( 10 ) of the component ( 4 ) of the sawtooth-shaped trailing edge ( 11 ) have a sawtooth-shaped profiling, which is opposite to the direction of the flow ( 17 ) over at least 20% up to 65% of a profile depth of the component ( 4 ). Aerodynamic component ( 4 ) according to claim 1, characterized in that at each sawtooth ( 10 ) in the main extension direction of the trailing edge ( 11 ) to a free end of the aerodynamic component ( 4 ), the shorter section ( 12 ) predominantly against the direction of buoyancy ( 5 ) or downforce and the longer section ( 13 ) a flat slope in the direction of buoyancy ( 5 ) or downforce. Aerodynamic component ( 4 ) according to claim 2, characterized in that at each sawtooth ( 10 ) of the sawtooth course in the main extension direction of the trailing edge ( 11 ) to the free end of the aerodynamic component ( 4 ), the shorter section ( 12 ) an inclination away from the free end of the aerodynamic component ( 4 ) having. Aerodynamic component ( 4 ) according to claim 1, 2 or 3, characterized in that at each sawtooth ( 10 ) the longer section ( 13 ) in the main extension direction of the trailing edge ( 11 ) 1.4 to 20 times longer than the shorter section ( 12 ) in the direction of buoyancy ( 5 ) or downforce is. Aerodynamic component ( 4 ) according to one of claims 1 to 4, characterized in that each shorter section ( 12 ) in the direction of buoyancy ( 5 ) or downforce has an extension which is 100 to 300% of the thickness of the boundary layer of the flow ( 17 ) in this region of the trailing edge ( 11 ) is. Aerodynamic component ( 4 ) according to one of claims 1 to 5, characterized in that the of the sawtooth-shaped trailing edge ( 11 ) Outgoing profiling not in the range of the largest profile thickness of the aerodynamic component ( 4 ) enough. Aerodynamic component ( 4 ) according to one of claims 1 to 6, characterized in that profile edges ( 18 ) of the profiling on the in the direction of the buoyancy ( 5 ) or output side of the aerodynamic component ( 4 ) in the direction of the flow ( 17 ) viewed from a free end of the aerodynamic component ( 4 ) are curved away while profile edges ( 18 ) profiling on the contrary to the direction of buoyancy ( 5 ) or output side of the aerodynamic component ( 4 ) in the direction of the flow ( 17 ) to the free end of the aerodynamic component ( 4 ) are curved out. Aerodynamic component ( 4 ) according to one of claims 1 to 7, characterized in that on each sawtooth ( 10 ) an equally strong vortex ( 7 ) at the trailing edge ( 11 ) of the aerodynamic component ( 4 ), which turns an opposite direction of rotation into a vortex ( 6 ), which at a free end of the aerodynamic component ( 4 ) arises. Aircraft with at least one aerodynamic component ( 4 ) according to one of claims 1 to 8.

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