Structural element for reducing a flow resistance

Abstract

A structural element for attachment to an outer panel of a vehicle, in particular a transport vehicle, a passenger car, a rail vehicle, an aircraft and / or a watercraft, comprises a main fin and at least one first and one second auxiliary fin. Said auxiliary fins are arranged next to the main fin in such a way that a first channel is formed between the first auxiliary fin and the main fin and a second channel is formed between the second auxiliary fin and the main fin. The first channel and the second channel each have a cross-sectional change such that, in the case of a throughflow of a fluid through the first channel or the second channel, a change in a throughflow velocity of the fluid occurs. In this way, the flow behaviour of a fluid around the vehicle can be influenced, and the flow resistance which acts on the vehicle can be effectively reduced. The invention also relates to a vehicle, a facade element, a fluid line and a sports suit. The invention likewise relates to a mounting aid for mounting structural elements on a surface.

Description

[0001] Structural element for reducing flow resistance

[0002] Technical area

[0003] The invention relates to a structural element for attachment to an outer skin of a vehicle, in particular a transport vehicle, a passenger car, a rail vehicle, an aircraft and / or a watercraft, which comprises a main fin and at least a first and a second secondary fin, which are arranged next to the main fin in such a way that a first channel is formed between the first secondary fin and the main fin and a second channel is formed between the second secondary fin and the main fin.

[0004] State of the art

[0005] Reducing flow resistance on surfaces over which air flows is a well-known problem in various technical fields. Various approaches have been tested in vehicle construction to reduce flow resistance. Typical approaches involve the shape of the vehicle's hull – through a suitable shape (e.g., teardrop shape or similar), flow resistance can be reduced.

[0006] However, especially for trucks, which are designed to have the largest possible transport volume, the design freedom is limited. Low flow resistance is also a goal for passenger cars. Here, too, the design freedom for the body shape is limited from both a technical and aesthetic perspective.

[0007] Therefore, due to today's vehicle designs, the relative motion between the medium (air and / or water) still leads to flow separation and, consequently, turbulence, which increases drag and thus the vehicle's energy consumption. This effect is more pronounced at higher speeds, as air resistance increases proportionally to the square of speed. This is particularly significant in long-distance transport.

[0008] There is therefore an effort to reduce the flow resistance of a vehicle - on the one hand for economic reasons, in particular to increase the cost efficiency of transport, and on the other hand for ecological reasons, since the energy requirements of vehicles are largely derived from fossil fuels.

[0009] The problem of reducing drag is not limited to road vehicles, however, but equally applies to rail vehicles, aircraft, watercraft such as boats, submarines, etc., or even suits such as tracksuits for activities like skiing. Even with static objects exposed to currents, such as building facades or water or air pipes, similar considerations play a role. Here, the problem is not fuel consumption, but rather the impact of forces that can cause unwanted vibrations, noise, or even damage.

[0010] One approach to optimizing flow behavior or reducing flow resistance is to modify the surface structure of a vehicle or other object. This can be achieved, for example, by incorporating structures that are small in size compared to the vehicle or object. These structures interact locally with the fluid flowing over the outer skin of the vehicle or object, thus influencing the flow behavior.

[0011] Previous solutions typically include one or more simple local elevations or depressions in the vehicle's outer skin or the object's surface. Solutions with several elevations of varying sizes, designed as fins, are also known.

[0012] GB 2481640 A (Adil Shazad), for example, discloses accessories for vehicles to increase their energy efficiency. The accessory comprises a base plate, a central fin, and a pair of side fins. This accessory can be attached to a surface of a vehicle to increase the vehicle's efficiency by creating wake vortices.

[0013] However, the known approaches to reducing the flow resistance of a vehicle or other object are not effective enough and lead to a relatively minor reduction in flow resistance.

[0014] Description of the invention

[0015] A first object of the invention is to provide a device belonging to the technical field mentioned at the outset, which effectively reduces the flow resistance acting on a vehicle and can be produced simply and inexpensively.

[0016] The solution to the problem is defined by the features of claim 1. According to the invention, the first channel and the second channel each have a cross-sectional change such that when a fluid flows through the first channel or the second channel, a change in a flow velocity of the fluid occurs.

[0017] The device is a structural element for attachment to the outer skin of a vehicle, in particular a transport vehicle, a passenger car, a rail vehicle, an aircraft, and / or a watercraft. It comprises a main fin, at least one first and one second secondary fin. The secondary fins are arranged next to the main fin in such a way that a first channel is formed between the first secondary fin and the main fin, and a second channel is formed between the second secondary fin and the main fin.

[0018] Changing the channel cross-section has an effect on the fluid that is comparable to the effect of a pipe through which fluid flows and whose inner diameter changes. According to a Venturi nozzle, for example, if the cross-section of the pipe tapers, the flow velocity behind the taper increases, while at the same time the hydrostatic pressure of the fluid decreases. A similar effect occurs in the first and / or second channel of the structural element. Changing the cross-section of the channel therefore preferably creates a change in the flow velocity when a fluid flows through the channel. This in turn makes it possible to create advantageous changes in the flow behavior around a vehicle by changing the channel cross-section. Unlike in a closed pipe, changing the flow within the channel also has an effect on the fluid flows above the channel.

[0019] This can also create a suction or injector effect above the structural element and the ducts. Experiments and simulations have shown that when a structural element is attached to the vehicle's outer skin, a negative pressure is created above the structural element during travel, which directs crossflows toward the structural element. These are then redirected in the structural element's ducts and can thus be aligned with the vehicle's main direction of travel. Here, the change in cross-section also affects the redirected crossflows.

[0020] It has now surprisingly been discovered that a change, and in particular a widening, of the channel cross-section along the flow direction has a positive effect on a vehicle's flow resistance, thus reducing energy consumption (e.g., gasoline, diesel, electrical energy, etc.). The flow resistance experienced by the vehicle from the surrounding fluid is thus effectively reduced. This, in turn, allows the vehicle to cover a distance with reduced fuel consumption compared to traveling the same distance and at the same speed without corresponding flow elements on its outer skin.

[0021] The structural element is a component that extends over the outer skin of the vehicle. As a result, the fluid surrounding the vehicle flows around the structural element in addition to the outer skin, or even instead of the outer skin, as soon as the vehicle is moving. Due to the flow element's effect on the fluid flows that form around the vehicle as the vehicle moves, the structural element changes the interaction between the vehicle and the fluid. For example, the flow element can change the flow resistance exerted on the vehicle through fluid mechanical effects. For example, the overall flow resistance of the vehicle can be partially reduced in the main direction of travel. Fluid mechanical forces acting on parts of the vehicle's outer skin can also be modified in such a way that the occurrence of oscillations or vibrations is reduced or suppressed.

[0022] A vehicle is any type of device that moves through a fluid that at least partially surrounds it. In particular, it includes a transport vehicle, a passenger car, a rail vehicle, an aircraft, and / or a watercraft. These vehicles typically have one or more main directions of travel. They are therefore designed to move primarily in this main direction of travel through the fluid that partially surrounds them.

[0023] The term "outer skin" refers here to at least a region of a vehicle surface along which the fluid flows while the vehicle is traveling in the main direction of travel. This results in a relative movement between the fluid and said outer skin while the vehicle is traveling in the main direction of travel. The outer skin is essentially flat and smooth, at least in the vicinity of the structural element. The outer skin may well have curvatures. Such curvatures preferably have a large radius of curvature in the region of the structural element, which is in particular greater than the length of the structural element, in particular greater than five times the length of the structural element.

[0024] A fluid, in turn, is understood to be any flowing substance that is capable of flowing around a body. In the context of the present application, it is the fluid that flows around a vehicle as it travels, in particular this is air or water. When traveling, a vehicle typically experiences flow resistance from the fluid flowing around it, which flow resistance slows the vehicle down and must be overcome by the vehicle. In the case of watercraft in particular, several fluids, in this case water and air, can flow around the vehicle and each exert a flow resistance on the vehicle. It is clear to a person skilled in the art that the fluid can also be inhomogeneous and can in particular comprise, for example, aerosols, smoke, fog, etc.

[0025] Induced drag represents a significant contribution to flow resistance. The vehicle generates movements within the fluid that are not parallel to the main direction of travel. The kinetic energy of these fluid movements is at least partially removed from the vehicle. These fluid movements, also referred to as crossflows, are generally undesirable from a fluid dynamics perspective. For example, in a transport vehicle, compensating flows can occur on the upper surface transverse to the main direction of travel, caused by air displacement.

[0026] In the following description, the terms top, bottom, above, below, top side, bottom side, etc. are used.

[0027] The structural element comprises a support surface, which in particular represents the surface with which the structural element comes into contact with a vehicle outer skin. The support surface is preferably flat. In certain embodiments, the structural elements can be at least slightly elastically or plastically deformable such that they can be attached to a non-flat surface, in particular, for example, a curved surface, such that the entire support surface contacts the surface. In this situation, the support surface essentially assumes the shape of the surface and thus no longer forms a plane. In variants, however, the support surface of the structural element can also be non-flat.

[0028] The part of the structural element that points away from the support surface is the top side of the structural element. Analogously, its bottom side is the part of the structural element that points in the same direction as the support surface. To orient lengths and heights, a plane called the principal plane is introduced. This principal plane has the same orientation as the support surface and contains it as long as the structural element is not deformed. Unless otherwise specified, a height is the smallest distance from a point to the principal plane. If height is used as a directional specification, this is a direction perpendicular to the principal plane. A length, in turn, refers to the distance between two points on the structural element that have the same height, i.e., run parallel to the support surface. If length is used as a directional specification, this refers to the direction parallel to the support surface or to the principal plane introduced above.

[0029] A fin, whether main or secondary fin, is a continuous area of ​​a structural element that is located on top of the structural element and extends above it. The height of the fin increases from the edge of the fin towards the fin. A fin is capable of at least partially displacing and thus redirecting the fluid in question. The length of a fin is the maximum length parallel to the support surface that can be found between two points on the fin. The height of a fin along its length is the maximum height that can be found at any position along its length and is measured perpendicular to the support surface.

[0030] The main fin is the fin that is preferably arranged in a central region of the structural element and / or has the greatest height and / or the greatest length among the fins. Particularly preferably, the main fin is a fin arranged in the central region of the structural element and has both the greatest height and the greatest length.

[0031] A secondary fin is a fin that is distinct from the main fin. The sidewalls of the secondary fin are different from the sidewalls of the main fin or other secondary fins. The secondary fin(s) are preferably arranged essentially parallel to the main fin.

[0032] A channel is a spatial area above the top side of the structural element, between the main fin and a secondary fin, through which a fluid can flow. The channel is defined in a first direction by the side walls of adjacent fins. In a second direction perpendicular to this first direction, along the channel, the channel is not defined by a fluid, but is open. The channel is also defined downwards (towards the main plane) by the surface of the flow element or, after attachment to a vehicle, by its outer skin. At the top, i.e. pointing away from the main plane, the channel is not necessarily defined; preferably, the channel is not defined upwards, or at least not completely defined. The spatial area referred to as the channel is continuous with a positive cross-section. The length of the channel corresponds to the length of the shorter fin that defines the channel.

[0033] The cross-section is a section of the channel along a plane perpendicular to the direction of the channel length. The channel cross-section is defined by a boundary line between the crests of the fins that define the channel. A positive channel cross-section exists if a continuous surface area exists within the cross-section that is delimited by the structural element or the side walls of the fins that define the channel in such a way that it can be completely enclosed by the boundary line introduced above and, at most, by the main plane introduced above.

[0034] A cross-sectional change refers to a change in the channel cross-section, wherein the channel cross-section at a first position along the channel length differs from a channel cross-section at a second position along the channel length. Thus, the channel cross-section at the first position is not identical to the channel cross-section at the second position, preferably not congruent, and particularly preferably not equal in area.

[0035] Preferably, the main fin and the first secondary fin, as well as the main fin and the second secondary fin, are not aligned parallel to each other. In variants, the main fin and the first secondary fin, or the main fin and the second secondary fin, can also be aligned parallel to each other. In this case, for example, the main fin can have a cross-sectional change along the longitudinal direction, whereby the first channel and the second channel also experience a cross-sectional change along the longitudinal axis.

[0036] Preferably, the first channel and / or the second channel are curvature-free, meaning that the side walls (essentially perpendicular to the support surface) of the main fin and in particular of the first and second secondary fins are designed such that no fluid deflection occurs within the first and second channels. This provides the least possible resistance to the fluid. In variants, the first channel and / or the second channel can include a curvature, allowing the fluid flow to be deflected parallel to the support surface.

[0037] Preferably, the main fin, and in particular the first and second secondary fins, are convex in a sectional plane parallel to the support surface. Thus, the main fin, and in particular the first and second secondary fins, preferably do not have any lateral indentations or the like. Tests have shown that this creates a structural element that can significantly reduce flow resistance. In variants, the main fin, and in particular the first and second secondary fins, can also include concave regions, and thus in particular indentations, grooves, and the like.

[0038] Preferably, a maximum width transverse to the longitudinal direction of the first channel and / or the second channel increases in the longitudinal direction, preferably over the entire length of the first channel and / or the second channel, at an opening angle between 0.1° and 20°, preferably between 0.5° and 10°, particularly preferably between 2.5° and 4.5°. Based on numerous prototypes and experiments in the flow channel, it was surprisingly demonstrated that a particularly effective reduction in flow resistance can be achieved with the above opening angles.

[0039] The maximum width of the channel is measured parallel to the support surface, transverse to the longitudinal direction of the channel. If the first and / or second channel has two parallel boundary walls, these boundary walls are arranged at an opening angle to one another as described above. In principle, the first and / or second channel can have a shape that cannot be easily described geometrically. The shape of the cross-section of the channel is therefore typically not necessarily geometrically similar at different points along the longitudinal direction. The maximum width therefore does not necessarily run along the longitudinal axis over a constant height above the support surface. The maximum height at which the maximum width of the channel can be determined at a location in the longitudinal direction is preferably determined by the height of the lower fin at this location.Particularly preferably, the maximum width increases continuously transversely to the longitudinal direction of the first channel and / or the second channel in the longitudinal direction. In variants, the first channel and / or the second channel can also have one or more regions in the longitudinal direction in which the maximum width is constant.

[0040] Preferably, the main fin ridge is not parallel to the first secondary fin ridge or the second secondary fin ridge. Particularly preferably, a main fin ridge is at an angle of between 0.1° and 20°, preferably between 0.5° and 10°, and particularly preferably between 2.5° and 4.5°, to the first secondary fin ridge or the second secondary fin ridge. In variants, the main fin ridge can also be aligned parallel to the first secondary fin ridge or the second secondary fin ridge.

[0041] Advantageously, the channels have a curved channel bottom in a central region along a respective longest channel length in a cross-section. This means that the channel's cross-section at least partially describes an upwardly directed curve.

[0042] Such a shape effectively channels the flow while minimizing the wall area exposed to the flow (while maintaining a constant fluid flow volume). This, in turn, reduces the friction that occurs when the flowing fluid comes into contact with the channel floor. At the same time, this shape also allows for a stable construction of the structural elements.

[0043] Alternatively, the channel can also have a rectangular cross-section, for example. However, while maintaining the same channel volume, the surface area of ​​the channel floor is increased, and thus the friction.

[0044] Preferably, the main fin has a cross-sectional change in the direction of the first channel and / or the second channel (i.e., in the longitudinal direction). Thus, the cross-sectional change of the first and / or the second channel can be achieved at least partially by the shape of the main fin. Particularly preferably, the main fin has a cross-sectional change along the longitudinal direction such that a height of the main fin changes. Further preferably, the main fin has a cross-sectional change along the longitudinal direction such that a width of the main fin changes.

[0045] In variants, the cross-sectional change of the main fin can be omitted. The cross-sectional change of the first and / or second channel can also be achieved by orienting the main fin relative to the first or second secondary fin (e.g., by arranging the main fin non-parallel to the first or second secondary fin). Furthermore, the cross-sectional change can also be achieved solely or additionally by changing the cross-sectional shape of the first and / or second secondary fin.

[0046] Preferably, the main fin, and in particular also the first secondary fin and the second secondary fin, has a width in an end region of the fin length and at a locally average fin height that corresponds to at least 30%, preferably at least 40% of the channel width. An end region of the fin length refers to a position along the respective fin length that is no further than 30% from a fin end. The locally average height is a height between 30% and 70% of the maximum fin height at this position. The fin width, in turn, is the maximum extension of the fin at this height and this length position, parallel to the support surface and transverse to the fin length. The channel width, in turn, is the width of the channel (or its clear dimension) transverse to the length of the main fin and parallel to the support surface, at the same height.Particularly preferably, the main fin, in particular also the first and second secondary fin, has a cross-section in an end region of the fin length which corresponds to at least 30%, in particular 40%, of the channel cross-section.

[0047] The advantage of this extension is that the fin is relatively wide in relation to the width of the channel. This means that the (first or second) channel itself, together with the adjacent fins, i.e. the main fin and the first or second secondary fin, represents a taper compared to the space in front of the structural element. This means that flows that were previously able to develop at this height are confined to a narrower space upon entering the channel. This in turn results in a Venturi effect, or suction effect, since the channel opening acts on the flow like a cross-sectional taper. It therefore causes an increase in flow velocity and a decrease in the hydrostatic pressure of the fluid. This can in turn direct further flows, in particular cross flows, towards the channel opening, which then aligns them in the channel with the main direction of travel of the vehicle.

[0048] Preferably, the main fin comprises a main fin comb and the first secondary fin comprises a first secondary fin comb, wherein a minimum distance between the main fin comb and the secondary fin comb is between 50% and 300%, preferably between 100% and 150% of a maximum height of the main fin.

[0049] The fin crest is a continuous line of the highest fin height, at least 50%, preferably 100%, of the fin length. The advantage of this variant is that the channel is as high as it is wide. A flow of a certain volume is thus exposed to the smallest possible channel surface area.

[0050] Alternatively, the fins can be spaced further or closer together. However, this increases the channel surface area per flow volume / flow cross-section, thus increasing friction.

[0051] Preferably, the main fin is symmetrical in shape to a plane perpendicular to the support surface and containing the fin crest. This ensures that no crossflows form above the main fin and that the force acting on the main fin is symmetrical.

[0052] Preferably, the main fin crest of the main fin, and in particular a first secondary fin crest of the first secondary fin and a second secondary fin crest of the second secondary fin, describes a curve in a plane perpendicular to the support surface, wherein the curve comprises a first curve section and a second curve section directly adjoining the first curve section, wherein the first curve section has an average pitch angle between 5° and 15°, in particular between 7° and 9°, particularly preferably between 7.4° and 8.0°. Particularly good results were achieved with a pitch angle between 7.6° and 7.8°, particularly preferably at approximately 7.7°. The term average pitch angle is to be understood as meaning that the pitch of the first section is determined between the support surface of the structural element and the highest point of the curve (i.e. the maximum height of the main fin).In between, the curve can deviate slightly from a straight line with the above gradient, in particular in a range of less than + / - 20%, in particular less than + / - 10%, particularly preferably less than + / - 5% of the maximum height of the curve. Preferably, the main fin crest has an indentation which has a depth of less than 20%, in particular less than 10% of the maximum height of the main fin. Tests have shown that this can achieve better results in reducing flow resistance. In variants, the indentation can also be omitted. Preferably, the first curve section has a wave shape with an amplitude of less than 20%, preferably less than 10% of the maximum height of the main fin. More preferably, the wave shape comprises exactly two wave crests.Preferably, a length of the first curve section projected perpendicularly onto the support surface is at least 75%, preferably at least 85%, in particular between 88% and 92% of the total length of the main fin.

[0053] In variations, the first curve section can also have an average angle of inclination of less than 5° or more than 15°. The length of the first curve section projected onto the support surface can also be less than 75% of the total length of the main fin. The first curve section can also be straight or otherwise deviate from a straight line.

[0054] Preferably, the curve of the main fin crest in the region of the second curve section describes a circular arc over an angle between 85° and 95°, in particular approximately 90°. The curve does not necessarily have to follow the exact shape of a circular arc, but can preferably deviate from the ideal circular arc line within a range of less than + / -10%, in particular less than + / -5%, particularly preferably less than + / -2% of the maximum height of the curve. In variants, the second curve section can also be shaped differently.

[0055] Particularly preferably, the structural element comprises a third secondary fin and a fourth secondary fin, wherein the third secondary fin is arranged directly next to the first secondary fin such that a third channel is formed between the third secondary fin and the second secondary fin, and wherein the fourth secondary fin is arranged directly next to the second secondary fin such that a fourth channel is formed between the fourth secondary fin and the second secondary fin. Increasing the number of channels results in more effective guidance of the fluid flows. Since the channels are open, in particular, towards the top, a channel also influences the flow behavior of the fluid that is located in the vicinity of the channel. The third and fourth channels can thus generate a secondary flow that also influences the fluid flow within the first and second channels.In addition, the third and fourth secondary fins, as well as the third and fourth channels, allow for further variation in their specific shape, based, for example, on their respective distance from the main fin. This allows, for example, larger and smaller channels to be combined, gradually absorbing and redirecting crossflows on the vehicle. The shapes of the fins can also be varied so that fins further out, which are exposed to stronger crossflows, offer a more slanted sidewall to counteract these flows than, for example, the main fin. The main fin itself can then take on a shape that effectively influences flows that run largely parallel to the main fin.Finally, with the larger number of fins or channels, a sufficiently efficient reduction of flow resistance can be achieved with relatively few structural elements per unit area, while the individual structural elements are still relatively small.

[0056] Preferably, the third and fourth secondary fins are each asymmetrical to a plane that is perpendicular to the support surface and in particular contains the respective fin crest. In particular, the height of the second or third secondary fin increases less steeply towards the fin crest on the side of the second or third secondary fin that points away from the main fin than on the opposite side. This ensures that cross flows from the structural element are effectively guided into the channels. In the channels, the flows are in turn held by the steeper walls and thus effectively deflected. Alternatively, the second or third secondary fin can also have a different shape, e.g. a shape symmetrical to the above-mentioned plane. Alternatively, additional secondary fins and channels can be dispensed with.

[0057] It is advantageous for the first and second channels to be longer than the third and fourth channels. The length refers to the maximum length of each channel. Since side currents perpendicular to the vehicle's main direction of travel cause the channeled currents to swirl again, shorter channels can specifically deflect these side currents, while the channels, which are partially formed by the main fin, exert their full effect on the currents already running parallel to the vehicle's main direction of travel.

[0058] Alternatively, the channels can be the same length. Furthermore, the outer channels (e.g., the third and fourth channels) can also be longer than the inner channels (in this case, the first and second channels).

[0059] In a preferred embodiment, the structural element is mirror-symmetrical to a plane running transversely to the main fin. By running transversely to the main fin, we mean that the plane of symmetry is essentially perpendicular to the length of the main fin and perpendicular to the support surface of the structural element. This results in a structural element that takes into account a changing main direction of travel of the vehicle. This means that the structural element has the same effect on flows, regardless of whether the vehicle is traveling forwards or backwards, for example. Vehicles that have two main directions of travel, such as many trains, also benefit from such a design. A corresponding structural element preferably has the shape of a double wedge (i.e. essentially the shape of an isosceles obtuse-angled triangle) in cross-section perpendicular to the support surface and parallel to the longitudinal direction.In particular, according to the above embodiment, the main fin crest (and analogously the first and second secondary fin crests, as well as any further secondary fin crests) can correspond to the first curve section and thus deviate to a certain extent from the ideal shape of an isosceles triangle. Tests have shown that this creates a compromise structural element that leads to a significant reduction in flow resistance for opposite main directions of travel. In an alternative preferred embodiment, the structural element does not exhibit such symmetry. For vehicles such as passenger cars or trucks, flow resistance when reversing is normally negligible. In this case, a flow element that is specifically optimized for one main direction of travel is advantageous.

[0060] Preferably, the structural element is mirror-symmetrical to a plane running parallel to the main fin, which is in particular perpendicular to the support surface and parallel to the longitudinal direction. This means that the plane contains a straight line that runs parallel to the main fin or the plane contains the maximum length of the main fin. Such a structural element reacts equally to cross flows from both directions transverse to the main fin. The frictional forces caused by the flow element itself from flows parallel to the main fin are also symmetrical. If the flow element is attached to a vehicle such that the main fin is parallel to the main direction of travel, no torque acts on the structural element. This in turn reduces the forces on the connection between the vehicle and the structural element.

[0061] Alternatively, a structural element that is not symmetrical in this plane may also be useful, particularly for selected surfaces of the vehicle, such as the side areas. Such a structural element can be designed with the prior knowledge that crossflows will preferentially attack from one direction and then specifically redirect these crossflows. This can be useful, for example, along an edge of a vehicle aligned with the flow direction. Other applications are known to those skilled in the art.

[0062] In a preferred embodiment of the invention, the main fin, and preferably all secondary fins as well, has a tangent angle of no more than 30°, preferably between 10° and 20°, at one end to a support surface of the structural element. This means that even a flat outer skin of a vehicle will form such a tangent angle with the fins. The term "tangent angle" here refers to the smallest angle that a tangent can form with a straight line running parallel to the structural element, with this angle being no more than 10% of the maximum length of the fin from a fin end. The term "tangent" in turn refers to a straight line that touches but does not intersect the fin crest. This has the advantage that when the structural element is attached to a vehicle, the fin end is pointed towards the vehicle's outer skin. This is capable of redirecting a fluid flow without generating turbulence.Alternatively, the main fin or the main fin and one or all of the secondary fins may have a different tangent angle to a lower side of the structural element.

[0063] Preferably, the maximum height of the secondary fins increases toward the main fin, and in particular, the main fin has the highest maximum height. This means that the maximum height of the secondary fins is greater the closer the secondary fin is to the main fin. The outermost secondary fins therefore have the lowest height. In particular, the main fin has the highest maximum height, i.e., a maximum height that is higher than the maximum height of all secondary fins. Particularly preferably, the height of the fins is also selected along the entire length of the main fin so that it increases toward the main fin.

[0064] This ensures that crossflows that do not meet the structural element in the direction of the channels are gradually absorbed and redirected by the fins. This allows crossflows to be absorbed by multiple channels without the inner channels being too heavily in the slipstream of the outer ones.

[0065] In a preferred embodiment, a height of the main fin and in particular a height of the first, second, third and fourth secondary fins increases continuously over at least 60%, in particular at least 80% of a total length of the main fin or secondary fin, wherein in particular the main fin and preferably the first, second, third and fourth secondary fins have or have a substantially wedge-shaped side profile.

[0066] Such a steadily increasing fin height allows the fins to be mounted on a vehicle in such a way that a fluid flow against the vehicle's main direction of travel encounters a steadily increasing fin height. This effectively guides the fluid flow without creating local turbulence near the channels.

[0067] Alternatively, the fin height can also be shaped differently. However, if the shape is incorrectly chosen, this would have the disadvantage of creating turbulence above the flow element, potentially making the channels less effective in modulating the fluid flow.

[0068] Preferably, the same number of secondary fins are located on both long sides of the main fin. Long sides refer to the two sides of a plane spanned by the height and maximum length of the main fin. This arrangement of secondary fins also ensures the same number of channels on both sides of the main fin. If such a structural element is aligned with the main fin in the main direction of travel, a largely symmetrical force effect is created on the structural element, meaning it does not experience any strong torque. Likewise, the structural element will have little or no asymmetrical reaction on the vehicle, allowing it to be positioned very freely on the vehicle's outer skin.

[0069] Alternatively, different numbers of secondary fins can be located on both long sides of the main fin.

[0070] Preferably, all fins each have a fin end that is located within an area whose extent parallel to the length of the main fin amounts to at most 20% of the length of the main fin. This means that along the main fin, the ends of the secondary fins are located on at least one side of the main fin, all on the same length along the main fin. With appropriate alignment of the structural element on the outer skin of a vehicle, it can be achieved that all ends of the fins (main and secondary fins) are in the same position relative to the main direction of travel of the vehicle and point away from it. In the event of vortex generation by the ends of a fin facing away from a fluid flow, this ensures that the vortices do not hit an adjacent fin and disrupt or influence the flow around it.

[0071] Alternatively, the ends can also be arranged differently, for example staggered. In the case of a flow element that is intended symmetrically for two opposite main directions of travel, the turbulence must be accepted. Particularly preferably, the length of the first, second, third and fourth secondary fins is each shorter than the length of the main fin, and the length of the secondary fins increases towards the main fin. This means that the maximum length per fin increases with proximity to the main fin, and the length of the main fin is greater than the length of all the secondary fins. In addition to the length of the channels, the different lengths of the fins can also result in the channel ends being angled in relation to the fin length. This means that cross flows are better absorbed into the channels and aligned with the main direction of travel. Alternatively, the fins can also be the same length.

[0072] In a preferred embodiment of the invention, the length of the structural element in the direction of the first channel is between 30 mm and 120 mm, preferably between 50 mm and 100 mm, particularly preferably between 80 mm and 90 mm. In a particularly preferred embodiment, the length is between 80 mm and 86 mm, in particular approximately 83 mm. A length means the maximum length of the structural element parallel to, or at an angle of up to a maximum of 20° to the maximum length of the first channel. In this extent, the structural element is effective in speed ranges that are relevant for the operation of vehicles. Furthermore, it is large enough to be easy to handle before being attached to the vehicle. The attachment itself is also simpler than, for example, with smaller elements. Cleaning is also easier than with smaller elements. Larger structural elements, in turn, are associated with higher manufacturing costs, for example.In addition, larger elements exert greater forces per structural element on the structural element or on the vehicle. This can complicate attachment to the vehicle. Another advantage of this size is that such a structural element can be manufactured using a 3D printing process, while still remaining within the typical size of components that a 3D printer can produce. At the same time, the lowest resolution of the 3D printer is not exceeded.

[0073] Alternatively, the structural element can also have a length less than 30 mm or a length greater than 120 mm. Preferably, a width of the structural element transverse to the first channel is between 20 mm and 100 mm, preferably between 40 mm and 80 mm, particularly preferably between 60 mm and 70 mm. In a particularly preferred embodiment, the width is between 61 mm and 67 mm, in particular approximately 64 mm. The width transverse to the first channel here means the maximum length of the structural element in a direction that is transverse to, or at an angle of between 90° and 80°, to the maximum length of the first channel. This width has the advantage that it allows the flow characteristics of a vehicle to be effectively influenced while at the same time being easy to maintain and install, with low friction forces and at low costs.

[0074] Alternatively, the width of the structural element transverse to the first channel can be less than 20 mm or more than 100 mm.

[0075] The maximum height of the main fin is preferably between 5 mm and 20 mm, preferably between 7 mm and 14 mm, and particularly preferably between 9 mm and 11 mm. In a particularly preferred embodiment, the maximum height is approximately 10 mm. Such a height has a number of advantages. The structural element thus rises sufficiently above the outer skin of a vehicle to effectively and positively influence its flow behavior. At the same time, the structure of the vehicle, and therefore its visual impression and design, is not disrupted by the structural element. Furthermore, the structural element therefore generally does not protrude above any antennas on the vehicle. Furthermore, a structural element of this height does not significantly increase the vehicle's susceptibility to wind. Likewise, structural elements of this type can even be placed on parts of the outer skin that are located in front of the driver's cab without blocking the driver's view.

[0076] Alternatively, a structural element with a height of less than 5 mm could be created. This would potentially have the disadvantage of being less effective than higher fin heights. Structural elements higher than 20 mm are also possible. However, this could increase the vehicle's susceptibility to wind.

[0077] Preferably, the maximum height of the first and second secondary fins is between 5 mm and 20 mm, preferably between 6 mm and 12 mm, and particularly preferably between 8 mm and 9 mm. In a particularly preferred embodiment, the maximum height is approximately 8.5 mm. In variants, the maximum height of the first and second secondary fins can also be less than 5 mm or greater than 20 mm.

[0078] Preferably, the maximum height of the third and fourth secondary fins is between 3 mm and 20 mm, preferably between 4 mm and 12 mm, and particularly preferably between 5 mm and 7 mm. In a particularly preferred embodiment, the maximum height is approximately 6 mm. In variants, the maximum height of the third and fourth secondary fins can also be less than 3 mm or greater than 20 mm.

[0079] In a preferred embodiment of the invention, the mass of the structural element is at most 20 g, preferably at most 15 g. Since the overall mass of the vehicle also influences fuel consumption, a structural element with a low mass is generally advantageous over one that is too heavy. However, the structural element should retain its dimensional stability even under relevant loads, since deformation would affect its flow properties. Structural elements weighing more than 20 g are also possible, although their contribution to the vehicle weight becomes more significant. In particular, structural elements made entirely or partially of plastic can achieve this weight.

[0080] The structural element preferably comprises a fastening device for attaching the structural element to the outer skin of a vehicle, in particular a transport vehicle, a passenger car, a rail vehicle, an aircraft, and / or a watercraft. A fastening device is a region of the structural element that comprises a configuration in which the fastening device is permanently connected to the outer skin of a vehicle. In the connected state, at least one surface of the fastening device touches the vehicle's outer skin and cannot be detached from this vehicle's outer skin. "Permanently connected" means that at least regular travel with the vehicle does not generate any flow, vibration, or friction forces capable of breaking the connection.

[0081] The fastening device can comprise functional parts that enable such fastening. For example, these can be clamps with which the structural element can be clamped to the vehicle's outer skin. Screws and receptacles for these screws are also possible. Another alternative is a prepared adhesive surface with a release liner. This release liner (which is not part of the structural element) is then removed before installation, and the structural element can then be bonded to the vehicle's outer skin.

[0082] Alternatively, the structural element does not include a fastening device. It can, for example, be placed or clamped into a designated indentation on the prepared vehicle outer skin. However, this only works with well-predictable flow forces or with appropriately designed vehicles. Furthermore, the structural element can be attached to the vehicle's outer skin with an adhesive. Multiple structural elements can also be attached to the outer skin using an external film (adhesive film). Other variants are known to those skilled in the art.

[0083] In a particularly preferred embodiment of the invention, the fastening device comprises at least one permanent magnet for fixing the structural element to the outer skin of a vehicle. Permanent magnets are all hard magnetic materials. Such a magnet allows the structural element to be attached to the magnetic outer skin of vehicles without manipulating the outer skin of the vehicle itself (e.g., by drilling holes). The magnet can, for example, be inserted in a form-fitting manner within a structural element. A structural element consisting exclusively of hard magnetic material is also possible.

[0084] Alternatively, the fastening device may have a different design and, for example, comprise clamps (see above). Alternatively, the structural element may not comprise a fastening device.

[0085] A further aspect of the invention is a vehicle comprising an outer skin which is exposed to a fluid, in particular water and / or air, while traveling in a main direction of travel, wherein at least 5, preferably at least 50, particularly preferably at least 250 structural elements according to the above description are attached to the outer skin of the vehicle to reduce driving resistance to the fluid. Attached here means, for example, that the structural elements have each been connected to the vehicle's outer skin by means of a fastening device. Alternatively, the structural elements can also be enclosed by the outer skin of the vehicle in such a way that they cannot become detached. Several structural elements can also be attached to the outer skin of the vehicle together with a fastening device. A larger number of structural elements increases the surface coverage of the vehicle's outer skin with structural elements.This can have a positive effect on the flow characteristics of the vehicle.

[0086] Preferably, the structural elements have a wedge shape with a wedge tip in cross-section, wherein the structural elements are aligned such that the wedge tip is aligned in the main direction of travel. Cross-section refers to a section through the structural element in which the cutting plane is parallel to the main direction of travel of the vehicle.

[0087] Preferably, the minimum distance between two adjacent structural elements on the outer skin is at least 50 mm, preferably at least 100 mm, and particularly preferably at least 150 mm. Tests have shown that a significant reduction in air resistance can be achieved even with a relatively small number of structural elements per unit area. This allows, for example, a vehicle to be equipped with the structural elements with relatively little effort. In variants, the minimum distance between two structural elements can also be less than 50 mm.

[0088] Preferably, the minimum distance between two adjacent structural elements on the outer skin is at most 500 mm, preferably at most 350 mm, and particularly preferably at most 250 mm. Again, experiments have shown that very large minimum distances between two adjacent structural elements significantly reduce their effectiveness. Therefore, the minimum distance is preferably less than 500 mm. In special embodiments, especially when, for example, the structural elements are particularly large, the minimum distance can also be more than 500 mm.

[0089] Preferably, a surface section of the vehicle's outer skin provided with the structural elements has a maximum of 100 structural elements per square meter, preferably a maximum of 50, particularly preferably a maximum of 10 structural elements, in particular, for example, 8 structural elements. In variants, more than 100 structural elements per square meter can be provided. Because the flow conditions and thus the vehicle's energy consumption can be optimized with a relatively small number of structural elements, existing vehicles can also be retrofitted with the structural elements relatively easily. For this purpose, the structural elements can, for example, be bonded to the vehicle's body parts.

[0090] Preferably, the structural elements are arranged one behind the other in rows offset at right angles to the flow direction. This achieves an efficient arrangement of the structural elements, with the structural elements being as far apart as possible while being relatively densely packed. In variants, the structural elements can also be arranged in non-staggered (Cartesian) rows.

[0091] Preferably, two adjacent structural elements on the outer skin of the vehicle in the rows oriented perpendicular to the flow direction have a minimum distance (smallest connecting line between the adjacent structural elements) in the range of 100% to 800%, in particular in the range of 250% to 500% of the maximum width of the structural element. In variants, however, the distance can also be less than 100% or more than 800% of the maximum width of the structural element.

[0092] Preferably, two structural elements arranged one behind the other and adjacent in the flow direction have a minimum distance (smallest connecting line between the adjacent structural elements) in the range of 100% to 800%, in particular in the range of 250% to 500% of the maximum width of the structural element. In variants, however, the distance can also be less than 100% or more than 800% of the maximum length of the structural element.

[0093] Another aspect of the invention is an assembly jig for assembling

[0094] Structural elements on a surface, comprising a frame and at least three alignment elements for aligning the structural elements, wherein the

[0095] Alignment elements are connected to the frame. The assembly jig allows for simple and quick parallel alignment of several structural elements on the outer skin of a vehicle. This allows a vehicle to be equipped with the structural elements easily and efficiently. The assembly jig preferably also includes suction cups for attachment to the vehicle's outer skin, allowing it to be easily and reversibly attached to the vehicle's outer skin. Alternatively, it can also be designed without suction cups.

[0096] Also preferred is an assembly jig whose frame is made of a material that includes aluminum. This allows for a robust construction with low weight. Alternatively, the frame can also be made of a material that does not include aluminum, for example, stainless steel or a plastic.

[0097] A preferred embodiment of the assembly jig comprises a flexible mat, in particular a rubber mat, in which the alignment elements consist of cutouts within the mat. The flexible mat, in particular the rubber mat, can form the frame of the assembly jig or supplement it. The cutouts are preferably cut into the flexible mat using water jet cutting. The advantage of this embodiment is that such a mat is very robust and easy to store. It is also very compact. Furthermore, the mat can be placed on a vehicle's outer skin quickly and reliably. Furthermore, the alignment elements can be cut into the mat in any number and orientation without incurring additional material costs. Alternatively, the assembly jig can also be constructed differently and not include a flexible mat.

[0098] A further aspect of the invention is a facade element for mounting on a building envelope of a building, comprising at least 5, preferably at least 20 structural elements for reducing wind-induced force effects on the facade element. When the facade element is mounted on a building envelope, the structural elements protrude from an outer side of the facade element by a height of at least 5 mm, preferably at least 8 mm. This results in a facade element that offers particularly low resistance in strong wind conditions or during a storm. This can reduce damage to the facade elements in extreme weather conditions.

[0099] Preferably, the structural elements are designed and arranged analogously to the structural elements described above in connection with the vehicles.

[0100] Preferably, a building envelope of a building is clad with at least one such facade element.

[0101] Preferably, a facade element provided with the structural elements has a maximum of 100 structural elements per square meter, preferably a maximum of 50, particularly preferably a maximum of 10 structural elements, in particular, for example, 8 structural elements. In variants, more than 100 structural elements per square meter can also be provided.

[0102] A further aspect of the invention is a fluid line, in particular a ventilation duct, with a main flow direction and at least one inner wall, wherein the fluid line comprises at least 5, preferably at least 20 structural elements for reducing turbulence in the fluid line during operation of the fluid line, wherein the structural elements stand out from the inner wall with a height of at least 5 mm, preferably at least 8 mm. In this way, a largely laminar flow can be achieved in a fluid line, in particular in a ventilation duct. This can reduce turbulence and stirring. Furthermore, a noise level and vibrations can be reduced. Furthermore, less energy is required for ventilation. The structural elements can also be used in water pipes, in particular in water pipes with a large cross-section.Furthermore, the fluid lines can also be used in hydroelectric power plants (high flow rates) or as pipelines for oil or gas transport (long transport distances). Experts are familiar with other areas of application.

[0103] Preferably, the structural elements are designed and arranged analogously to the structural elements described above in connection with the vehicles.

[0104] Preferably, an inner wall of a fluid line provided with the structural elements has a maximum of 100 structural elements per square meter, preferably a maximum of 50, particularly preferably a maximum of 10 structural elements, in particular, for example, 8 structural elements. In variants, more than 100 structural elements per square meter can also be provided.

[0105] A further aspect of the invention is a sports suit which, when worn by a person during use, has a main direction of travel and comprises an outer skin which is exposed to a fluid, in particular water and / or air, during travel in the main direction of travel. The outer skin comprises at least 5, preferably at least 20 structural elements for reducing the driving resistance to the fluid, wherein the structural elements protrude from the outer skin by a height of at least 5 mm, preferably at least 8 mm.

[0106] Preferably, the structural elements are designed and arranged analogously to the structural elements described above in connection with the vehicles.

[0107] Preferably, a tracksuit provided with the structural elements has a maximum of 100 structural elements per square meter, preferably a maximum of 50, particularly preferably a maximum of 10 structural elements, in particular, for example, 8 structural elements. In variants, more than 100 structural elements per square meter can also be provided.

[0108] Further advantageous embodiments and combinations of features of the invention emerge from the following detailed description and the entirety of the patent claims. Brief description of the drawings

[0109] The drawings used to explain the embodiment show:

[0110] Fig. 1 a shows a first embodiment of the structural element in direct plan view,

[0111] Fig. 1 b the first embodiment of the structural element as a direct side view,

[0112] Fig. 1 c the first embodiment of the structural element in cross sections,

[0113] Fig. 1 d the underside of the first embodiment of the structural element in isometric plan view,

[0114] Fig. 2 shows a second embodiment of the structural element in isometric

[0115] top view,

[0116] Fig. 3 a vehicle with structural elements in isometric top view and

[0117] Fig. 4 a first assembly template for structural elements in isometric plan view,

[0118] Fig. 5 a second assembly template for structural elements in isometric top view.

[0119] In principle, identical parts in the figures are provided with identical reference symbols.

[0120] Ways to implement the invention

[0121] Figures 1a-1d show various views of a structural element 10 according to the invention for attachment to the outer skin of a vehicle. Fig. 1a shows the top side of the structural element 10 as a direct plan view, Fig. 1b shows a direct side view of the structural element 10, Fig. 1c shows several cross-sections through the structural element 10, and Fig. 1d shows the underside of the structural element 10 in an isometric plan view.

[0122] The structural element 10 comprises a main fin 10a, centrally positioned as seen from above (Fig. 1a), a first secondary fin 10b, a second secondary fin 10c, a third secondary fin 10d, and a fourth secondary fin 10e. The secondary fins 10b and 10c are located to the sides of the main fin 10a in plan view, while the secondary fins 10d and 10e are located to the outside and to the sides of the secondary fins 10b and 10c, respectively.

[0123] The first secondary fin 10b is arranged such that, together with the main fin 10a, it forms a first channel 11h. The second secondary fin 10c, together with the main fin 10a, forms a second channel 11i. The third secondary fin 10d, together with the first secondary fin 10b, forms a third channel 11j. Similarly, the fourth secondary fin 10e, together with the second secondary fin 10c, forms a fourth channel 11k.

[0124] The length of the structural element 10, parallel to the first channel 11h, corresponds to the maximum length of the main fin 10a and, in this embodiment, is 85 mm. Perpendicular to this length, i.e., perpendicular to the first channel 11h or the main fin 10a, the maximum extension of the structural element 10 is 67 mm. The maximum height of the structural element 10 again corresponds to the maximum height of the main fin 10a and is 10 mm. The total mass of the structural element 10 is 14.5 g.

[0125] The main fin 10a is an elongated protrusion located centrally within the structural element 10. The main fin 10a is longer than the secondary fins 10b - 10e. It has an elongated horizontal outline, with its maximum width (vertical in the image plane of Fig. 1a) accounting for approximately 17% of its maximum length (horizontal in the image plane of Fig. 1a). The width of the main fin 10a varies depending on the height (vertical to the image plane of Fig. 1a). Within the upper 10% of its height, the width of the main fin 10a remains constant over its entire length. In a middle region of its height and along a large part of its length, the width of the main fin 10a increases linearly by approximately 100% from a first end to a second end. Towards the second fin end, the width then tapers from its maximum back to its original value.

[0126] The height of the main fin 10a (vertical in the image plane of Fig. 1 b) is at most approximately 15% of the maximum length of the main fin 10a. The position of the maximum height has a distance along the length of the main fin from a first end of the main fin that approximately corresponds to the maximum height. The maximum height thus divides the main fin 10a along its length into a first section between the maximum height and the first end of the main fin 10a and a second section between the maximum height and the second end of the main fin 10a. On the first section, the height from the end to the maximum height follows the shape of a quarter circle, i.e. it rises vertically at the fin end and then becomes horizontal again at the maximum. On the second, longer section, the height of the main fin 10a falls continuously and almost linearly from the maximum height to the second fin end.This results in an essentially wedge-shaped side profile of the main fin 10a.

[0127] In cross-section (Fig. 1c, AA, BB or CC), cut along a plane spanned by a height of the main fin 10a and a line (A, B or C in Fig. 1c) perpendicular to its maximum length, the height of the main fin 10a is rounded around the fin crest. Thus, the maximum height of the main fin 10a is centrally located with respect to its width at any point along its length. The side walls of the main fin 10a taper outwardly, essentially concavely, away from the fin crest of the main fin 10a until they are perpendicular to the height of the main fin 10a (horizontally in the image plane of Fig. 1c, A - A, B - B, C - C).

[0128] Along its length (horizontally in the image plane of Fig. 1 a), the main fin 10a is always higher than all secondary fins 10b - 10e and thus defines the lateral profile of the structural element 10 (Fig. 1 b).

[0129] The first secondary fin 10b and the second secondary fin 10c are symmetrical to each other, with the mirror plane spanned by the maximum length and maximum height of the main fin. The fin crests of the two secondary fins 10b and 10c are each inclined toward the main fin in the horizontal plane (Fig. 1a), i.e., the shortest distance between the fin crest at one end of a secondary fin 10b or 10c and the fin crest of the main fin 10a is shorter than at the other end of the secondary fin 10b or 10c.

[0130] At a mid-height, the secondary fins 10b and 10c have a triangular horizontal outline. This means that the width of a secondary fin 10b or 10c increases linearly along its maximum length from a first end to a second end and tapers again at its greatest width toward the second end, towards the main fin 10a. The maximum width is approximately 200% of the minimum width of the secondary fin 10b or 10c at the same height.

[0131] The height of the secondary fins 10b and 10c is the same as that of the main fin 10a, with the height along the length of the secondary fins 10b or 10c always being smaller than that of the main fin 10a (Fig. 1b). The height of the secondary fin 10b or 10c is approximately 90% of the height of the main fin 10a.

[0132] Even in cross-section (Fig. 1 c), cut along a plane spanned by a height of the main fin 10a and a line (A, B, or C in Fig. 1 c) transverse to its maximum length, the course of the side walls of the secondary fin 10b or 10c is very similar to that of the main fin 10a. Only in section plane C (Fig. 1 c) does the increasing width of the secondary fins 10b or 10c become apparent on the side facing away from the main fin 10a.

[0133] The outboard secondary fins 10d and 10e are shorter than the main fin 10a or the secondary fins 10b and 10c. Their maximum length is approximately 50% of the maximum length of the main fin 10a. In a region of their mid-height, the secondary fins 10d and 10e maintain their maximum width over a length section of approximately 40% of their maximum length, with their horizontal contours forming a wedge shape similar to the vertical profile of the main fin 10a. In this wedge shape, the side facing away from the adjacent secondary fin is rounded and tapers to one end of the secondary fin 10d or 10e.

[0134] The height profile (Fig. 1 b) of the third and fourth secondary fins 10d and 10e corresponds again to the height profile of the main fin 10a or the second and third secondary fins 10b and 10c.

[0135] The ducts 11h and 11i, formed by the main fin 10a and one secondary fin 10b or 10c, respectively, run essentially parallel to the main fin 10a. Their length is limited by the length of the main fin 10a and the secondary fins 10b and 10c. In a central region along the duct length, the duct 11h or 11i is completely bordered downwards by the side walls of the main fin 10a and one secondary fin 10b or 10c, i.e. in the cross-section (see Fig. 1c) there is only an opening at the top. Towards the ends of the duct length, the duct floor is only completed when the flow element is attached to the outer skin of a vehicle. At the fin ends, there is therefore no continuous connection between the fins (10a and 10b or 10c) in a direction perpendicular to the length of the main fin 10a.

[0136] In cross-section (Fig. 1 c), the channels are delimited by the side walls of the respective fin (10a, 10b, 10c). The side walls of the main fin 10a and the secondary fins 10b and 10c run concavely away from the respective highest height of the fin in the cross-section. The side walls of the main fin 10a and a secondary fin 10b or 10c meet in a middle region of the channel length so that a continuous, upwardly curved channel bottom is produced. The cross-section of the channel bottom changes along the length of the main fin 10a or along the channel length. Thus, the distance between the side walls of the main fin 10a and a secondary fin 10b or 10c is smaller at a middle height at the position of the intersection line C than at the same height but at the position of the intersection line A.

[0137] When a fluid flows through the first channel 1 1j or the second channel 1 1i, a change in the flow velocity of the fluid occurs.

[0138] Channel 11j is defined by the side walls of the first secondary fin 11b and the third secondary fin 10d. Similarly, channel 11k is formed by secondary fins 10c and 10e. Due to the shorter and flatter secondary fins 10d and 10e, channels 11j and 11k are shorter and flatter than channels 11h and 11i located next to the main fin 10a.

[0139] Channels 11j and 11k also have a round, upwardly open channel bottom in a middle section of their length, formed by the side walls of the adjacent secondary fins 10b and 10d or 10c and 10e. However, their cross-section changes only slightly between lines A and C.

[0140] Fig. 1d shows the underside of the structural element 10 in an isometric plan view. The structural element 10 comprises a fastening device 12 for attaching the structural element to the outer skin of a vehicle, consisting of a support surface and five permanent magnets 12a-12e. The permanent magnets 12a-12e are each located within recesses on the underside of the fins 10a-10e. The shape of the permanent magnets 12a-12e approximately corresponds to the shape of the respective fin 10a-10e, but with a smaller volume. Thus, the permanent magnet 12a under the main fin 10a is longer than the permanent magnets 12b-12e under the secondary fins 10b-10e.

[0141] The underside of the permanent magnets 12a - 12e is flush with the support surface. The support surface, in turn, surrounds the recesses within the fins 10a - 10e and is flat. With the fastening device 12, the structural element can be attached to the outer skin of a vehicle without further manipulation. A vehicle can thus be equipped or retrofitted with one or more structural elements 10.

[0142] Fig. 2 shows an alternative embodiment of the invention, the structural element 20. In the structural element 20, the fin arrangement is similar to that of the structural element shown in Fig. 1a - Fig. 1d. Here, too, the main fin 20a is longer than the adjacent first secondary fin 20b and the adjacent second secondary fin 20c. The first and second secondary fins 20b and 20c, respectively, are in turn longer than the third secondary fin 20d and the fourth secondary fin 20e. The main fin 20a forms a first channel 21h with the first secondary fin 20b. Analogously, the main fin 20a forms the second channel 21i with the second secondary fin 20b. The first secondary fin 20b also forms a third channel 21j with the third secondary fin 20d and the second secondary fin 20c forms the fourth channel 21k with the fourth secondary fin 20e.

[0143] The shape, length, and height of the structural element 20 result from the shape of the structural element 10 shown in Fig. 1a - Fig. 1d in combination with a plane spanned by the maximum height and a line perpendicular to the maximum length of the main fin 10a. On one side of the plane thus constructed lies a longer section of the structural element 10 and on the other side a shorter section. To construct the structural element 20 from Fig. 2, the shorter section is discarded and the longer section is mirrored across the constructed plane and assembled with the first section. This results in a structural element 20 that is mirror-symmetrical to a plane running perpendicular to the main fin. The effect of this structural element 20 on flows is the same if these flows are mirrored across a plane running perpendicular to the main fin. Such a symmetrical effect is particularly suitable for rail vehicles.

[0144] The cross-sectional change of the first and second channels 20h and 20i of the structural element 20 is also symmetrical, ie the cross-section of the channel 20h or 20i differs at two positions, on the same side of the symmetry plane transverse to the main fin 20a, but not at positions on both sides of the symmetry plane, with the same distance to the symmetry plane.

[0145] Figure 3 shows a schematic representation of an oblique view of a small van 30, wherein the outer skin is provided with structural elements 100.

[0146] The small van 30 comprises a driver's cab 31 with a spoiler 32 and a box body 33 with an outer skin 35. In the present case, the spoiler 32 as well as the side surfaces and the top surface of the box body of the small van 30 are provided with structural elements 100 at regular intervals. This reduces the air resistance of the small van 30, which on the one hand reduces fuel consumption and on the other hand also reduces vibrations and thus the noise level. In this exemplary embodiment, the driver's cab 31 is not provided with the structural elements. In a further variant, the side surfaces of the driver's cab 31 are additionally provided with structural elements 100. It is clear to those skilled in the art that other vehicles can also be provided with the structural elements, in particular vehicles used on long-distance routes with high average speeds (e.g., trucks in long-distance transport, etc.).), railway carriages, but also cargo ships, etc.

[0147] The structural elements 100 have the same shape as the structural element 10 shown in Fig. 1a - Fig. 1d. Thus, they have a wedge shape in cross-section and in side view. The structural elements 100 are aligned on the van 30 such that the wedge tip is aligned in the main direction of travel.

[0148] Figure 4 shows a schematic representation of an assembly jig 40 for mounting structural elements (10, 20, 100) on an outer skin. The assembly jig 40 comprises a rectangular frame 41, to which, in this case, three alignment elements 42a-42c are attached, with which the three structural elements can be positioned and secured to an outer skin. It also comprises a contact piece 43 with which it can contact an outer skin in addition to the alignment elements 42a-42c, wherein the contact piece 43 additionally supports the assembly jig 40.

[0149] Figure 5 shows a second assembly jig 50 for assembling structural elements (10, 20, 100). This assembly jig 50 comprises a flexible aluminum frame 51, with which a plurality of structural elements can be positioned and secured to an outer skin. It comprises several attachment pieces, e.g., attachment piece 53, and a plurality of alignment elements, e.g., alignment element 52. The assembly jig 50 can be reversibly attached to an outer skin using suction cups, e.g., suction cup 54. This makes it very easy to position this assembly jig on an outer skin and then firmly attach it.

[0150] The invention is not limited to the illustrated embodiments. In particular, the fins can have a different height profile and, for example, differently shaped side walls. In variants, the structural element can also comprise more than five fins or only three fins, i.e., one main fin and two secondary fins. The channels can have a different length relative to one another. The ends of the fins can also have a different shape than that illustrated here. Vehicles other than the one illustrated can also be equipped with the structural elements according to the invention. Likewise, the structural elements can be attached to the vehicle in an arrangement different from that illustrated. The assembly template according to the invention also has alternative embodiments. For example, it can comprise different numbers of alignment elements.

[0151] In summary, it can be stated that a structural element with a main fin and at least two secondary fins, which together with the main fin form channels with a changing cross-section, creates a structural element that is suitable for effectively reducing the flow resistance acting on a vehicle and is simple and cost-effective to manufacture.

Claims

Patent claims 1. Structural element for attachment to the outer skin of a vehicle, in particular a transport vehicle, a passenger car, a rail vehicle, an aircraft and / or a watercraft, comprising: a) a main fin; b) at least one first and one second secondary fin, which are arranged next to the main fin in such a way that a first channel is formed between the first secondary fin and the main fin and a second channel is formed between the second secondary fin and the main fin; characterized in that c) the first channel and the second channel each have a change in cross-section such that a change in the flow velocity of the fluid occurs when a fluid flows through the first channel or the second channel.

2. Structural element according to claim 1, characterized in that a maximum width transverse to the longitudinal direction of the first channel and / or the second channel increases in the direction of the longitudinal direction, preferably over the entire length of the first channel and / or the second channel, at an opening angle between 0.1° and 20°, preferably between 0.5° and 10°, particularly preferably between 2.5° and 4.5°, and in particular continuously.

3. Structural element according to claim 1 or 2, characterized in that the main fin has a change in cross-section in the direction of the first channel and / or the second channel.

4. Structural element according to one of claims 1-3, characterized in that the main fin comprises a main fin ridge and the first secondary fin comprises a first secondary fin ridge, wherein there is a minimum distance between the The main fin ridge and the secondary fin ridge are located between 50% and 300%, preferably between 100% and 150%, of the maximum height of the main fin. A structural element according to any one of claims 1-4, characterized in that the structural element comprises a third secondary fin and a fourth secondary fin, wherein a) the third secondary fin is arranged directly adjacent to the first secondary fin such that a third channel is formed between the third secondary fin and the second secondary fin, and wherein b) the fourth secondary fin is arranged directly adjacent to the second secondary fin such that a fourth channel is formed between the fourth secondary fin and the second secondary fin. A structural element according to claim 5, characterized in that the first channel and the second channel are longer than the third channel and the fourth channel.A structural element according to any one of claims 1-6, characterized in that the structural element is mirror-symmetrical about a plane extending transversely to the main fin. A structural element according to any one of claims 1-7, characterized in that the structural element is mirror-symmetrical about a plane extending parallel to the main fin. A structural element according to any one of claims 1-8, characterized in that the main fin, and preferably also all secondary fins, has a tangent angle of at most 30°, preferably between 10° and 20°, to an underside of the structural element at one end. A structural element according to any one of claims 5-9, characterized in that the maximum height of the secondary fins increases towards the main fin, and in particular the main fin has the highest maximum height.

1. Structural element according to one of claims 5-10, characterized in that the height of the main fin and in particular the height of the first, second, third and fourth secondary fins increases continuously over a partial length of at least 60%, in particular at least 80% of a total length of the main fin or secondary fin, wherein in particular the main fin and preferably the first, second, third and fourth secondary fins have a substantially wedge-shaped side profile.

12. Structural element according to one of claims 5 - 1 1 , characterized in that the same number of secondary fins are located on both longitudinal sides of the main fin.

13. Structural element according to claim 1, characterized in that all fins each have a fin end directly adjoining the partial length, which is located within an area whose extent parallel to the length of the main fin is at most 20% of the length of the main fin.

14. Structural element according to one of claims 5 - 13, characterized in that the length of the first, second, third and fourth secondary fin is each less than the length of the main fin and the lengths of the secondary fins increase towards the main fin.

15. Structural element according to one of claims 1 - 14, characterized in that the length of the structural element in the direction of the first channel is between 30 mm and 120 mm, preferably between 50 mm and 100 mm, and particularly preferably between mm and 90 mm.

16. Structural element according to one of claims 1 - 15, characterized in that the width of the structural element transverse to the first channel is between 20 mm and 100 mm, preferably between 40 mm and 80 mm, and particularly preferably between 60 mm and 70 mm.

17. Structural element according to one of claims 1 - 16, characterized in that a maximum height of the main fin is between 5 mm and 20 mm, preferably between 7 mm and 14 mm, particularly preferably between 9 mm and 11 mm.

18. Structural element according to one of claims 1 - 17, wherein the mass of the structural element is at most 20 g, preferably at most 15 g.

19. Structural element according to one of claims 1-18, comprising a Fastening device for attaching the structural element to the outer skin of a vehicle, in particular a transport vehicle, a passenger car, a rail vehicle, an aircraft and / or a watercraft.

20. Structural element according to claim 19, characterized in that the fastening device comprises at least one permanent magnet for fixing the structural element to the outer skin of a vehicle.

21. Vehicle comprising an outer skin which is exposed to a fluid, in particular water and / or air, during travel in a main direction of travel, wherein at least 5, preferably at least 50, particularly preferably at least 250 structural elements according to one of claims 1 - 20 are attached to the outer skin of the vehicle to reduce driving resistance to the fluid.

22. Vehicle according to claim 21, characterized in that the structural elements have a wedge shape with a wedge tip in a cross-section, wherein the structural elements are oriented such that the wedge tip is oriented in the main direction of travel.

23. Assembly jig for mounting structural elements on a surface, comprising a frame and at least three alignment elements for aligning the structural elements, wherein the alignment elements are connected to the frame.

24. Facade element for mounting on a building envelope of a building, characterized in that the facade element comprises at least 5, preferably at least 20, in particular preferably at least 250 structural elements according to claim 1 for reducing wind-induced forces on the facade element.

25. Building comprising a building envelope with at least one facade element according to claim 24. A fluid line, in particular a ventilation duct, with a main flow direction comprising at least one inner wall, wherein the fluid line comprises at least 5, preferably at least 20, and particularly preferably at least 250 structural elements according to claim 1 for reducing turbulence in the fluid line during operation, wherein the structural elements protrude from the inner wall. A sports suit, which, when worn by a person, has a main direction of travel in use, wherein the sports suit comprises an outer skin which, during travel in the main direction of travel, is exposed to a fluid, in particular water and / or air, characterized in that the outer skin comprises at least 5, preferably at least 20 structural elements according to claim 1 for reducing the driving resistance relative to the fluid, wherein the structural elements protrude from the outer skin.

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