Fluid-dynamically acting component comprising a profiled hump

Abstract

A fluid-dynamically acting component (2) comprises a mechanically supported component root (3), a free-ended component tip (6), a span (5) between the component root (3) and the component tip (6), a low-pressure side (7), a high-pressure side (8), a component airfoil (14), and a profiled hump (12) on the high-pressure side (8). The profiled hump (12) deforms the component airfoil (14) relative to a basic shape (15) of the airfoil, is limited to an area of ​​the local depth (18) of the airfoil, and extends at least over an outer area of ​​80% to 90% of the span (5), but is limited to an area between 10% and 30% of the span (5).The component profile (14) is designed for a flow (9) in the transonic velocity range, in which a lower pressure forms on the depression side (7) relative to the overpressure side (8) and a supersonic flow zone terminates with a compression shock, but no supersonic flow zone terminates with a compression shock forms on the depression side, and in which the profiled hump (12) counterbalances the flutter of the component (2). Figure for the abstract: Fig. 1.

Description

Title of the invention: Fluid-dynamically acting component comprising a profiled bump. Technical field of the invention

[0001] The invention relates to a fluid-dynamically acting component comprising a profiled bump. The invention relates in particular to a fluid-dynamically acting component having the characteristics of the preamble of independent claim 1.

[0002] The invention further relates to devices comprising several fluid-dynamic components of this type. The fluid-dynamic component can thus be one of the two wings of an aircraft. However, it can also be any other lifting surface, such as, for example, a hydrofoil or a rotor blade, including a rotor blade of a wind turbine or helicopter and a turbine blade of a turbomachine. The component can therefore be aerodynamically efficient, but also generate lift in a liquid.

[0003] A fluid-dynamically active component, which is mechanically supported only at its root, tends, under certain flow conditions, to float, that is, to undergo alternating deformations including large deviations of the component's tip, induced by the flow over the component. Such floating calls into question both the operation and the integrity of the fluid-dynamically active component.

[0004] The risk of wing flutter is particularly high in the transonic speed range, in which a spatially limited supersonic flow zone forms on the upper surface of the wing and terminates in a compression shock. In this case, an alternating migration of the compression shock in the direction of the flow over the component, and in the opposite direction, can lead to what is known as flow mode flutter over the component. State of the art

[0005] Document DE 10 2009 001 953 A1 refers, as a passive measure to influence wave drag on transonic wings, to the installation of profiled bumps on the flow-exposed surface, which induce geometric compression prior to the compression shock. The profiled bumps thus extend the pressure increase zone in the flow near the wall. The resulting multi-impact structure is significantly more favorable in terms of induced wave drag than a localized compression shock. The best effect is obtained with localized 3D bumps that generate relatively moderate self-drag in the design area.

[0006] As reported by J. Nitzsche et al.: "The effect of shock control bumps on the transonic flutter and buffeting characteristics of a typical wing section," International Forum on Aeroelasticity and Structural Dynamics, IFASD 2022, June 13-17, 2022, Madrid, Spain, a profiled bump called a "shock control bump" is described. This bump is formed in the supersonic flow zone on the upper surface of a wing and reduces the wing's tendency to flutter in transonic flow. For the transonic flow zone, an average position of the profiled bump at 50% of the airfoil depth and a length of the profiled bump of 20% of the airfoil depth are specified to place it close to the compression shock. The height of the profiled bump varies between 0.1% and 0.5% of the airfoil depth depending on the specific embodiment.The profiled hump shifts the occurrence of buffeting to higher angles of attack of the wing and thus prevents the flow mode from fluctuating in an area where, without the profiled hump, buffeting would previously have occurred.

[0007] A wing comprising the features of the preamble of claim 1 is known from US patent 7,118,071 B2, wherein a profiled hump extends downward from the underside to control compression impacts on it. The profiled hump is positioned to generate a defined downward impact under flight conditions in which compression impacts may occur on the underside. These conditions are Mach numbers close to 1.0, and the profiled hump is intended to expand the flight envelope of an aircraft at these Mach numbers. The profiled hump extends over the entire wingspan, or a plurality of profiled humps are distributed over the entire wingspan. Objective of the invention

[0008] The invention aims to provide a fluid-dynamically acting component with a profiled bump exhibiting improved fluid-dynamic properties at a lower cost. Solution

[0009] The objective of the invention is achieved by a fluid-dynamically acting component comprising the characteristics according to independent claim 1. Dependent claims 2 to 13 relate to preferred embodiments of the fluid-dynamically acting component according to the invention. Claim 14 relates to a two-winged aircraft, each wing being a component according to the invention; and claim 15 relates to a rotor with rotor blades, each blade being a component according to the invention. Description of the invention

[0010] In a fluid-dynamically acting component according to the invention, comprising a mechanically supported component root, a free-ended component tip, a span between the component root and the component tip, a depression side, an overpressure side, a component profile that has, transversely to the span, a maximum local profile thickness between the depression side and the overpressure side and a local profile depth, and a profiled hump that deforms the component profile relative to a basic profile shape that is limited to an area of ​​the local profile depth and that extends over an outer area of ​​the span, i.e., at least over an area of ​​the span close to the free end of the component, the component profile being designed for flow along the local profile depth, so that a lower pressure develops on the depression side than on the overpressure side,and in which the profiled bump counterbalances the component's float, the profiled bump being arranged on the overpressure side.

[0011] With regard to the depression side and the overpressure side of the component mentioned here, it is a matter of expressing nothing more than the fact that a lower pressure develops on the depression side than on the overpressure side during the flow along the local depth of the profile for which the component profile is designed.

[0012] The use of the adjective "local" in this description and in the claims, for example for "local profile depth", takes into account the fact that the value thus designated may vary depending on the wingspan. The local value is always the value at the point considered on the wingspan.

[0013] In the fluid dynamic component according to the invention, the span is regularly greater than an average depth of the component's profile. Generally, the span is at least three times greater than the average depth of the component's profile. The span can also be up to 100 times greater than the average profile depth of the component. Often, the span is no more than 50 times the average depth of the component's profile.

[0014] The profiled hump of the fluid dynamically acting component according to the invention is not arranged at the point of a compression shock that could form on the negative pressure side of the component, but rather on the opposite positive pressure side. Even if a supersonic flow zone is formed on the positive pressure side of the component, it does not result in a compression shock that could interact with the profiled hump on the positive pressure side. Nevertheless, the profiled hump causes a significant reduction in the fluttering tendency of the fluid dynamically acting component according to the invention. At the same time, a significant increase in the lift coefficient Ciift and / or a significant increase in the moment coefficient Cmy and / or a significant reduction in the drag coefficient Cdrag is observed under the same conditions. flow compared to an otherwise identical component without the profiled bump. Eliminating flutter by means of the profiled bump arranged according to the invention on the overpressure side of the component therefore does not come at the cost of other disadvantages in terms of fluid dynamics, but is at least potentially associated with other advantages in terms of fluid dynamics.

[0015] The basic profile shape of the component according to the invention is preferably designed for flow along the local profile depth in the transonic velocity range, i.e., it is optimized. By transonic velocity range, we mean the velocity range in which the aforementioned spatially limited supersonic zone, terminating in a compression shock in the flow, forms on the low-pressure side of the component. A supersonic flow zone can also occur on the high-pressure side, in the case of flow in the transonic velocity range, as also mentioned, which can in principle extend over the entire high-pressure side of the component, but which does not result in a compression shock in the flow. The spatial extent of such a supersonic flow zone on the high-pressure side of the component is also considerably reduced by the profile hump according to the invention arranged at this location.

[0016] In concrete terms, the basic shape of the profile can be a so-called supercritical flow profile. From the supercritical flow profile, the component profile of the component according to the invention deviates from the overpressure side in a manner locally limited by the profiled hump.

[0017] The profiled hump according to the invention is typically formed in an area extending over 25% to 70% of the local depth c of the profile, preferably over a range of 30% to 65% of the local depth of the profile, that is to say, approximately in the middle and with a slight tendency towards the forward half of the local depth of the profile. The profiled hump generally extends over 15% to 35%, and preferably over 20% to 30%, that is to say, about 25% of the local depth of the profile.

[0018] In the wingspan direction, the profiled hump according to the invention extends over at least 80% to 90% of the wingspan. Preferably, the profiled hump covers at least 75% to 95% of the wingspan. The profiled hump according to the invention is limited to an area between 10% and 30% of the wingspan, and preferably to an area between 15% and 25%, that is, approximately one-fifth of the wingspan.

[0019] The height of the profiled hump above the basic shape of the profile preferably has a continuous curvature, starting at zero and ending at zero, with a constant derivative as a function of the profile depth and, preferably, also with a constant derivative as a function of the span. The maximum local height of The profiled hump above the basic shape of the profile is generally between 3% and 15%, and preferably between 4% and 12%, of the maximum local thickness of the profile and / or generally between 0.2% and 1.2%, and preferably between 0.4% and 0.8%, of the local depth of the profile. In particular, considering the fluid dynamics effect it produces, the profiled hump according to the invention is relatively flat.

[0020] More specifically, the profile of the component deformed by the profiled bump relative to the basic shape of the profile may have on the overpressure side a locally limited front zone, concavely curved, in front of the maximum local height of the profiled bump, and / or a locally limited rear zone, concavely curved, in front of the maximum local height of the profiled bump.

[0021] Instead of appearing as a bump on the overpressure side, rising to a height relative to the basic profile shape on the depression side of the component, the profiled bump can be a cavity on the overpressure side which is lowered relative to the basic profile shape over a depth, towards the depression side of the component.

[0022] A person skilled in the art will optimize the exact position, dimensions and shape of the profiled hump for the specific use in order to achieve its main objective by means of the profiled hump, namely the suppression of flutter, the increase of lift in terms of fluid dynamics and the reduction of drag in terms of fluid dynamics for a given flow.

[0023] The profiled hump according to the invention can be permanently formed on the overpressure side of the component, which is generally not a disadvantage given the significant increase in the lift coefficient Ciift and / or the significant increase in the moment coefficient Cmy and / or the significant reduction in the drag coefficient Cdrag. In principle, however, there may be an actuation system designed to form the profiled hump on the overpressure side as the transonic speed range is approached and to remove it after leaving the transonic speed range.

[0024] An aircraft is a concrete application of the fluid dynamic component according to the invention. In this case, the two wings can be formed as components according to the invention, their efficiency in terms of fluid dynamics being aerodynamic efficiency, and the low-pressure and high-pressure sides of the component being the upper and lower surfaces of each wing. Thanks to the profiled hump according to the invention, with a constant angle of attack of a wing relative to its flow of AoA = 2.25°, a constant Mach number of its flow M = 0.865, and a constant static pressure of its flow Po = 55 kPa, the lift coefficient Ciift of the wing was increased by more than 4%. The moment coefficient Cmy was increased by more than 1%, the drag coefficient Cdrag was reduced by more than 5%, and the system damping was increased to a positive value, corresponding to the elimination of flutter. The wing had a supercritical airfoil shape. With a constant angle of attack AoA = 2.95°, a constant Mach number of the flow M = 0.865, and a constant static flow pressure Po = 70 kPa, the lift coefficient Ciift was increased by more than 5%, the moment coefficient Cmy was increased by more than 3%, the drag coefficient Cdrag was reduced by more than 7%, and the system damping was also increased to a positive value.

[0025] A rotor according to the invention comprising rotor blades, each of which is a component according to the invention, can be, for example, the rotor of a wind turbine, the rotor of a helicopter or the rotor of a turbomachine, in which the rotor blades are then turbine blades. Advantages of the invention

[0026] The advantageous developments of the invention are apparent from the claims, the description, and the drawings. The advantages of the features and combinations of several features mentioned in the description are provided by way of example only and may act alternatively or cumulatively without requiring the advantages of embodiments according to the invention.

[0027] Regarding the content of the disclosure—and not the scope of protection—of the original application documents and the patent, the following is stated: other features are shown in the drawings—in particular, the geometries shown and the relative dimensions of several components with respect to one another, as well as their relative arrangement and operational connection. Combining features from different embodiments of the invention or features from different claims is also possible in a manner different from the chosen references in the claims and is thus suggested. This also applies to features shown in separate drawings or mentioned in their description. These features can also be combined with features from different claims.Similarly, the features listed in the claims may be omitted for other embodiments of the invention, but this does not apply to claims independent of the granted patent.

[0028] The features mentioned in the claims and in the description should be understood, with regard to their number, as having exactly that number or a number greater than the number mentioned, without it being necessary to explicitly use the adverb "minimum". Thus, for example, when we speak Regarding a profiled bump, it should be understood that there is exactly one profiled bump, two profiled bumps, or more profiled bumps. The features mentioned in the claims may be supplemented by other features or be the only features of the object, depending on the claim in question.

[0029] The reference symbols contained in the claims do not constitute a limitation of the scope of the subject matter protected by the claims. They serve only to make the claims easier to understand. Brief description of the figures

[0030] The invention is explained and described in more detail below with reference to preferred embodiments illustrated in the figures.

[0031] Fig. 1 is a bottom view of a fluid-dynamically acting component according to the invention, designed in the form of a wing.

[0032] The [Fig.2] is a component profile of the wing according to the [Fig.1], transverse to its wingspan.

[0033] Figure 3 schematically illustrates different curvatures of the height of a profiled hump of the wing in the section according to Figure 2; and

[0034] Figures 4 to 7 are representations of the different bumps profiled according to [Fig.3] in a Cartesian grid. Description of the implementation method

[0035] The wing 1 shown in [Fig. 1], of an aircraft not shown, is an example of an aerodynamic component 2 according to the invention. The component 2 has a component root 3, the mechanical support 4 of which is represented here only symbolically. From the component root 3, the component 2 extends over a span 5 to a component tip 6. A low-pressure side 7 and a high-pressure side 8 of the component 2, seen directly in [Fig. 1], extend in the direction of a flow 9 extending transversely across the span 5 from a leading edge 10 to a trailing edge 11. On the high-pressure side 8, a profiled hump 12 is formed in an outer area of ​​the span 5 near the component tip 6. A line 13 on [Fig.l] indicates a section extending transversely to the span 5 through component 2 in the area of ​​the profiled hump 12, which is shown in the following figure.

[0036] [Fig. 2] shows, by means of a solid line, a component profile 14 of component 2 along a section along line 13 of [Fig. 1]. In the area of ​​the local profiled hump 12, a basic profile shape 15 is represented by a dashed line, from which the component profile 14 differs with the profiled hump 12. Compared to this basic profile shape 15, referred to herein as the supercritical flow profile, the component profile 14 is locally convex downwards at the level On the other hand, overpressure 8. A maximum local height 16 of the profiled bump is here 0.5 mm, which is slightly more than 4% of a maximum local profile thickness 17 of 12 mm and slightly more than 0.4% of a local profile depth 18 of 12 cm. In this case, the ratio between the maximum local profile thickness 17 and the local profile depth 18 is exactly equal to 1 to 10.

[0037] Figure 3 shows four possible curvatures of the profiled hump 12 along the flow direction 9, i.e., along the section or component profile 14 as shown in Figure 2. The X-axis indicates the relative position with respect to the length of the hump in the thickness direction 18 of the profile, and the Z-axis indicates the relative height of the profiled hump 12 above the basic shape of the profile with respect to its maximum local height 16, as shown in Figure 2. All the curvatures shown of the height of the profiled hump 12 above the basic shape 15 of the profile represent a continuous curvature starting at zero and ending at zero, with a continuous derivative with respect to the depth of the profile.The profile 14 of the component deformed by the profiled bump 12 with respect to the basic shape 15 of the profile has, on the overpressure side 8, a limited front area 19 curved concavely, in front of the maximum local height 16 of the profiled bump 12, and a limited rear area 20 curved concavely, behind the maximum local height 16 of the profiled bump 12. .

[0038] In concrete terms, the curvature marked by circles and designated "Poly-4" in [Fig.3] is a fourth degree polynomial: f(x) = h(16x2 -32x 3 +16x 4 ) with x between 0 and 1 and h as a height scale factor.

[0039] [Fig.4] shows this curvature in a Cartesian grid. In the principal direction of extension of the profiled hump 12 along the span 5, i.e. the Y direction on [Fig.4], the profiled hump 12 is smoothed by the Hermite polynomials f(y) = 3x2-2x3 or f(y) = l-3x2+2x3.

[0040] The curvature of the profiled hump 12, marked by asterisks and designated "Poly-6" in [Fig. 3], is that of a sixth-degree polynomial. [Fig. 5] shows its extension and smoothing in the Y direction of the span 5.

[0041] The curvature of the profiled hump 12, marked by squares and designated "Poly-8" in [Fig. 3], is that of an eighth-degree polynomial. [Fig. 6] shows its extension and smoothing in the Y direction of the span 5.

[0042] A curvature of the profiled hump 12 according to a cosine function is marked in [Fig. 3] by triangles and is designated "1-Cos". [Fig. 7] shows the expansion and smoothing of this curvature in the Y direction of the span 5.

[0043] The profiled hump 12 influences the aerodynamic coefficients of moment, lift and drag, as well as the overall damping of the aeroelastic system of the wing 1 according to [Fig. 1], as shown in Tables 1, 2 and 3 below for three different cases of Mach number, static pressure and angle of attack. The positive influence on aerodynamic lift and aerodynamic drag is particularly noteworthy.

[0044] [Table 1]: Influence of the local shape change on the underside of the effective aerodynamic wing on the aerodynamic coefficients and on the damping of the system at a constant angle of incidence of AoA = 2.25°, constant Mach number of 0.865 and constant static pressure Po = 55kPa. Basic configuration (without shape change) Lower side hump Max. height = 0.5 mm Lower side hump Max. height = 1.0 mm Lift coefficient Clift [-] 0.3868 0.4112 (+6.3%) 0.4058 (+4.9%) Moment coefficient Cmy [-] -0.1376 -0.1416 (+2.9%) -0.1394 (+1.3%) Drag coefficient [-] 0.0264 0.02475 (-6.3%) 0.02476 (-6.2%) System attenuation [%] -0.021 +0.0215 +0.0215

[0045] [Table 2] : Effect of the local shape change on the lower face of the aerodynamically efficient wing on the aerodynamic coefficients and on the damping of the system at a constant angle of incidence of AoA=2.95°, constant Mach number of 0.865 and constant static pressure Po=7OkPa. Basic configuration (without shape change) Lower side hump Max. height = 0.5 mm Lower side hump Max. height = 1.0 mm Lift coefficient Clift [-] 0.41333 0.44181 (+6.9%) 0.44220 (+7.0%) Moment coefficient Cmy [-] -0.13519 -0.14056 (+4.0%) -0.13999 (+3.6%) Drag coefficient C^ [-] 0.029166 0.026419 (-9.4%) 0.026619 (-8.7%) System attenuation [%] -0.0173 +0.0119 +0.0122

[0046] [Table 3] : Effect of the local shape change on the lower face of the aerodynamically efficient wing on the aerodynamic coefficients and on the damping of the system at a constant angle of incidence of AoA=3.05°, constant Mach number of 0.865 and constant static pressure Po=7OkPa. Basic configuration (without shape change) Lower side hump Max. height = 0.5 mm Lower side hump Max. height = 1.0 mm Lift coefficient Cnft [-] 0.42650 0.45301 (+6.2%) 0.45344 (+6.3%) Moment coefficient Cm y [-] -0.13554 -0.14051 (+3.7%) -0.13997 (+3.3%) Drag coefficient C^g [-] 0.029619 0.026803 (-9.5%) 0.027007 (-8.8%) System attenuation [%] -0.141 +0.0132 +0.0135 List of reference signs

[0047] 1 Wing

[0048] 2 Component

[0049] 3 Component placement

[0050] 4 Mechanical support

[0051] 5 Wingspan

[0052]

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[0055]

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[0060]

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[0065]

[0066] 6 Component tip 7 Low pressure side 8 High pressure side 9 Flow 10 Leading edge 11 Trailing edge 12 Profile hump 13 Line 14 Component profile 15 Profile base shape 16 Maximum local height of profile hump 12 17 Maximum local thickness of profile 18 Local depth of profile 19 Curved front concave area 20 Curved rear concave area

Claims

Demands

1. Fluid-dynamically acting component (2) comprising: - a mechanically supported component root (3), - a free-ended component tip (6), - a span (5) between the component root (3) and the component tip (6), - a low-pressure side (7), - a high-pressure side (8), - a component profile (14) which, transversely to the span (5), has a maximum local profile thickness (17) between the low-pressure side (7) and the high-pressure side (8) and a local profile depth (18), and - a profiled hump (12) which deforms the component profile (14) relative to a basic profile shape (15), which is limited to an area of ​​the local profile depth (18) and which extends at least over an outer area of ​​80% to 90% of the span (5), - the component profile (14) being designed for a flow (9) along the local depth (18) of the profile,so that a lower pressure develops on the depression side (7) than on the pressure side (8), - the basic shape (15) of the profile being designed for flow along the local depth (18) of the profile in the transonic velocity range, in which a spatially limited supersonic flow zone terminating in a compression shock forms on the depression side (7), and - the profiled hump (12) being arranged on the pressure side (8), characterized - in that no supersonic flow zone terminating in a compression shock forms in the transonic velocity range on the pressure side (8), - in that the profiled hump (12) is limited to a range between 10% and 30% of the span (5), - in that the profiled hump (12) counterbalances the flutter of the component (2) along the local depth (18) of the profile during the flow (9).

2. Component (2) according to claim 1, characterized in that The profiled hump (12) under the same flow conditions causes a significant increase in the lift coefficient Ciift and / or a significant increase in the moment coefficient Cmy and / or a significant reduction in the drag coefficient Cdrag compared to a component without a profiled hump.

3. Component (2) according to claim 1 or claim 2, characterized in that the basic shape of the profile is a supercritical flow profile.

4. Component (2) according to any one of the preceding claims, characterized in that no supersonic flow zone forms in the transonic velocity zone on the overpressure side (8).

5. Component (2) according to any one of the preceding claims, characterized in that the profiled hump (12) is formed in a range between 25% and 70%, and preferably between 30% and 65%, of the local depth (18) of the profile.

6. Component (2) according to any one of the preceding claims, characterized in that the profiled hump (12) extends over 15% to 35%, and preferably over 29% to 30%, of the local depth (18) of the profile.

7. Component (2) according to any one of the preceding claims, characterized in that the profiled hump (12) covers at least the outer area of ​​75% to 95% of the span (5).

8. Component (2) according to any one of the preceding claims, characterized in that the profiled hump (12) is limited to a range between 15% and 25% of the span (5).

9. Component (2) according to any one of the preceding claims, characterized in that a height or depth of the profiled hump (12) relative to the basic shape (15) of the profile has a continuous curvature, starting at zero and ending at zero, with a constant derivative as a function of the local depth (18) of the profile, and preferably also as a function of the span (5).

10. Component (2) according to any one of the preceding claims, characterized in that a maximum local height (16) or a maximum local height of the profiled hump (12) relative to the basic shape (15) of the profile is between 3% and 15%, and preferably between 4% and 12%, of the maximum local thickness (17) of the profile and / or between 0.2% and 1.2%, and preferably between 0.4% and 0.8% of the local depth (18) of the profile.

11. Component (2) according to claim 10, characterized in that the component profile (14) deformed by the profiled bump (12) with respect to the basic shape (15) of the profile on the overpressure side (8) comprises, in front of the maximum local height (16) or the maximum local height of the profiled bump (12), a limited front area (19), curved concavely, and / or, behind the maximum local height (16) or the maximum local height of the profiled bump (12), a limited rear area (20), curved concavely.

12. Component (2) according to any one of the preceding claims, characterized in that the profiled bump (12) is permanently formed on the overpressure side (8).

13. Component (2) according to any one of the preceding claims, characterized in that an actuation system is provided to form the profiled bump (12) on the overpressure side (8) as the transonic velocity range is approached.

14. Two-winged aircraft (2) each wing being designed in the form of a component according to one of the preceding claims.

15. Rotor with rotor blades, each of which is designed in the form of a component (2) according to any one of the preceding claims.

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