NL2018382B1 - Vortex-reducing device and method - Google Patents

Abstract

The invention provides a vortex-reducing device for deducing the aerodynamic forces of airflows on an elongated structure part having a longitudinal axis, said vortex-reducing device comprising a senes of rings for mounting around said elongated structure part, each ring having a height, an inner periphery for clamping around said elongated structure part, and comprising at least two indents at an angle with respect to said longitudinal axis and which said angle having a predefined relation to said inner periphery for holding wires in a predefined spiralling way on the elongated structure part.

Description

Field of the invention

The invention relates to a vortex-reducing device and method.

Background of the invention

Many buildings and other constructions can be subjected to high a aerodynamic load due to for instance airflow around these buildings and constructions.

High chimneys, for instance, can be provided with so called “helical strakes” or “vortex shredders” in order to reduce vortices behind these chimneys in order to reduce vortex induced vibration (VIV). The phenomenon is mostly present in structures with a circular cross section. However, these helical strakes also have a significant drawback - they induce massive increases in drag and side forces that have significant structural implications for the chimney.

More recently, The Erasmu shrug in Rotterdam suffered from swinging of its stay cables due to the wind. Special dampers needed to be installed to solve this problem.

For many constructions, there is no solution for the problem of aerodynamic load due to wind or motion.

Summary of the invention

A disadvantage of prior art is that no solution is provided for aerodynamic loads of structure parts.

Hence, it is an aspect of the invention to provide an alternative device for reducing or adjusting aerodynamic loads on structure parts. To that end, the invention provides a vortex-reducing device for deducing the aerodynamic forces of airflows on an elongated structure part having a longitudinal axis, said vortex-reducing device comprising a series of rings for mounting around said elongated structure part, each ring having a height, an inner periphery for clamping around said elongated structure part, and comprising at least two indents at an angle with respect to said longitudinal axis and which said angle having a predefined relation to said inner periphery for holding wires in a predefined spiralling way on the elongated structure part.

In an embodiment, the indents with angle a helps applying the wires at the right angle, and securing the wires at the right pitch. Furthermore, the devices may additionally provide a means for mounting other functional parts, like lighting elements.

It was found that at relatively low Reynolds numbers, it proved to reduce vibration introduced by vortex shedding on structural parts due to disturbance of the Von Karman vortex street in the flows of air.

In an embodiment, the angle is such that said spiralling wires have a pitch of 613 times an inner diameter of said rings. In a particular embodiment, the pitch is 9-11 times the inner diameter of the rings.

In an embodiment, said indents are at an angle of 32°-12°. In a particular embodiment, the angle is determined with respect a line that is parallel to the axis of the devices.

In an embodiment, the indents have a size for holding a wire having a diameter of between 0.07-0.13 times the inner diameter of said rings. In particular the diameter is 0.08-0.11 times the inner diameter of said rings.

In an embodiment, the rings are mounted at a pre-set distance from one another for holding said wires spiralling at said angle, said pre-set distance having a predefined relation with respect to said inner periphery.

In an embodiment, the rings are arranged for holding at least three wires functionally spiralling. In an embodiment, said at least three wires are held spiralling in a functionally parallel manner, forming functionally a multiple helix.

In an embodiment, the ring has a functionally circular inner periphery, in particular said ring having an inner surface functionally defining a circle cylinder portion.

In an embodiment, the rings have an inner diameter of between 20 and 250 mm. In an embodiment, the rings comprises an alignment identification for aligning said rings with one another.

In an embodiment, the rings are moulded, in particular moulded from a polymer material.

In an embodiment, the rings are made of relatively light weight material to reduce the influence on the natural vibration of the structure. Such materials may comprise polymer material. Alternatively or in combination, such materials may comprise metals like aluminium, magnesium, or mixtures thereof. Alternatively, composite materials may be used, or for instance foamed material. Alternatively, a design optimizing wall thicknesses and reinforcement ribs may also reduce weight.

In an embodiment, least part of said rings comprise a lighting element, in particular at least part of said rings comprise a housing for a said lighting element.

In an embodiment, the vortex-reducing device further comprises a power line connecting said rings, in particular wherein said rings comprise a clamp for holding said power line, with said clamp providing said alignment identification.

The invention further pertains to a vortex-reducing assembly comprising a series of said vortex-reducing devices, and wires for holding in a predefined spiralling way on the elongated structure part.

In an embodiment, the elongated structure part is part of a structure, the devices comprising at least one lighting element, and said assembly further comprising a control device that is functionally coupled to the lighting elements of the devices.

In an embodiment, the control device comprises one or more images, the positions of the lighting elements on said structure, and a data processor for running a computer program which, when running on said data processor calculates a lighting element illumination setting for the lighting elements using said positions of said lighting elements such that the lighting elements together provide the visual illusion of the image.

In an embodiment, the control device comprises a series of images and a time frame, thus representing a motion picture part, and said computer program when running calculates a time series of lighting element illumination settings for the lighting elements using said positions of said lighting elements such that the lighting elements together provide a visual illusion of said motion picture part.

In an embodiment, the assembly further comprises a measuring device for measuring a motion of said structure, with said measuring device functionally coupled with said control device for providing motion data to said control device, and wherein said computer program, when running on said data processor calculates a dynamic position for the lighting elements using said motion data, and calculates said lighting element illumination settings using said dynamic positions for providing said visual illusion of said motion picture part.

The measuring device may, in an example of a rotating Ferris wheel, provide a rotational speed. From the rotational speed, the computer program in an embodiment calculates for each lighting element its speed (or a displacement vector). Thus, for each lighting elements a dynamic position with respect to a fixed observer may be calculated. It may even be possible to take into account the effect of vibrations in the structure or structural part. These measuring devices are as such known to a skilled person. It can comprise a displacement sensor, like a rotational speed sensor. In addition or in stead, a vibration sensor may be used that measures vibration in the structural part. Form the vibration data from such a vibration sensor, a dynamic position for the lighting elements may be calculated using their position on the structural part and the vibration data or rotational speed data.

The lighting elements thus in fact provide pixels in a pixel matrix, allowing an image to be projected. The pixels in an embodiment have a dynamic position in the image frame or matrix. For instance, a position of the lighting elements as a function of time with respect to a fixed observer can be calculated. Thus, in a matrix, dynamic pixels are provided. The control device controls an illumination setting for the lighting elements. This allows controlling light color, light intensity, and timing of these values. The control device may comprise a memory for holding one or more images. In an embodiment, the memory can further hold motion data from the measuring device.

It may be possible to use the wires (the helical wires) for providing power to the lighting devices.

The control device may comprise a PLC, a computer device, a series of coupled computer devices or distributed computer devices. These devices may be functionally coupled for instance via a remote, wired or wireless coupling. The control device may be functionally coupled to the lighting elements and to the measuring device via a wireless or wired coupling.

The invention further relates to a method for reducing aerodynamic forces of airflows on elongated structure parts, in particular on cables and tubes, more in particular having a diameter of between 40 and 250 mm, wherein said vortex-reducing device according to any one of the preceding claims is mounted on an elongated structural part, holding said wires spiralling about said elongated structural part.

The devices can also comprise molded metal parts, for instance molded parts from steel in case high impact resistance is required.

The invention further pertains to a lighting assembly for mounting on an elongated structure part of a structure, said assembly a line comprising lighting elements spaced apart on said line, and a series of devices for mounting on said elongated structure part and holding said line on said structure part, said devices comprising a ring for mounting around said structural part and said rings comprising a housing for a said lighting element. The lighting assembly allows using a structure as a basis fir projecting an image, a series of images, or even motion pictures or movies.

In an embodiment of said lighting assembly, said lighting assembly further comprising a control device that is functionally coupled to the lighting elements of the devices, wherein said control device comprises one or more images, the positions of the lighting elements on said structure, and a data processor for running a computer program which, when running on said data processor, calculates a lighting element illumination setting for the lighting elements such that the lighting elements together provide the visual illusion of the image.

The terms “upstream” and “downstream” relate to an arrangement of items or features relative to the propagation of the light from a light generating means (here the especially the first light source), wherein relative to a first position within a beam of light from the light generating means, a second position in the beam of light closer to the light generating means is “upstream”, and a third position within the beam of light further away from the light generating means is “downstream”.

The term “substantially” herein, such as in “substantially consists”, will be understood by the person skilled in the art. The term “substantially” may also include embodiments with “entirely”, “completely”, “all”, etc. Hence, in embodiments the adjective substantially may also be removed. Where applicable, the term “substantially” may also relate to 90% or higher, such as 95% or higher, especially 99% or higher, even more especially 99.5% or higher, including 100%. The term “comprise” includes also embodiments wherein the term “comprises” means “consists of’.

The term functionally will be understood by, and be clear to, a person skilled in the art. The term “substantially” as well as “functionally” may also include embodiments with “entirely”, “completely”, “all”, etc. Hence, in embodiments the adjective functionally may also be removed. When used, for instance in “functionally parallel”, a skilled person will understand that the adjective “functionally” includes the term substantially as explained above. Functionally in particular is to be understood to include a configuration of features that allows these features to function as if the adjective “functionally” was not present. The term “functionally” is intended to cover variations in the feature to which it refers, and which variations are such that in the functional use of the feature, possibly in combination with other features it relates to in the invention, that combination of features is able to operate or function. For instance, if an antenna is functionally coupled or functionally connected to a communication device, received electromagnetic signals that are receives by the antenna can be used by the communication device. The word “functionally” as for instance used in “functionally parallel” is used to cover exactly parallel, but also the embodiments that are covered by the word “substantially” explained above. For instance, “functionally parallel” relates to embodiments that in operation function as if the parts are for instance parallel. This covers embodiments for which it is clear to a skilled person that it operates within its intended field of use as if it were parallel.

Furthermore, the terms first, second, third and the like in the description and in the claims, are used for distinguishing between similar elements and not necessarily for describing a sequential or chronological order. It is to be understood that the terms so used are interchangeable under appropriate circumstances and that the embodiments of the invention described herein are capable of operation in other sequences than described or illustrated herein.

The devices or apparatus herein are amongst others described during operation. As will be clear to the person skilled in the art, the invention is not limited to methods of operation or devices in operation.

It should be noted that the above-mentioned embodiments illustrate rather than limit the invention, and that those skilled in the art will be able to design many alternative embodiments without departing from the scope of the appended claims. In the claims, any reference signs placed between parentheses shall not be construed as limiting the claim. Use of the verb to comprise and its conjugations does not exclude the presence of elements or steps other than those stated in a claim. The article a or an preceding an element does not exclude the presence of a plurality of such elements. In the device or apparatus claims enumerating several means, several of these means may be embodied by one and the same item of hardware. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage.

The invention further applies to an apparatus or device comprising one or more of the characterising features described in the description and/or shown in the attached drawings. The invention further pertains to a method or process comprising one or more of the characterising features described in the description and/or shown in the attached drawings.

The various aspects discussed in this patent can be combined in order to provide additional advantages. Furthermore, some of the features can form the basis for one or more divisional applications.

Brief description of the drawings

Embodiments of the invention will now be described, by way of example only, with reference to the accompanying schematic drawings in which corresponding reference symbols indicate corresponding parts, and in which:

Figure 1 a perspective view of embodiments of the device holding wires on a tube end;

Figure 2 a side view of figure 1;

Figure 3 a cross section as indicated in figure 2;

Figure 4 a perspective view of an embodiment of the device shown in figure 1 in detail;

Figure 5 the device of figure 4 in exploded view;

Figure 6 the rear part of the device of figure 5;

Figure 7 an alternative device, also shown in figures 1 and 2, detailed and in perspective view;

Figure 8 the device of figure 7 in top view;

Figure 9 the device of figure 8 in cross section as indicated.

The drawings are not necessarily on scale.

Description of preferred embodiments

Figure 1 shows a perspective view of embodiments of the device 3, 4 holding wires 5 a cylindrical part, here on a tube end 2. Figure 2 shows a side view of figure 1, and figure 3 a cross section as indicated in figure 3.

In this embodiment, the devices 3, 4 are mounted on an elongated structure part 2, here a tube end that may be part of a larger construction. Alternatively, the large structure part 2 may also be another cylindrical part. Often, such a cylindrical part will be circle-cylindrical. For instance, such a part can be a cable, for instance a steel wire cable. These parts in general have a circular cross section. In larger constructions, these elongated construction parts may suffer from high aerodynamic loads. In particular, elongated construction parts that have a functionally circular cross section, as shown in the cross section indicated in figure 2 and depicted in figure 3, may suffer from this. In windy conditions, vortexes may form behind these structural parts. When these vortices have a frequency which is close to the structural frequency (or eigenfrequency) of the structural part, the structural part may come into resonance.

The device 3, 4 comprises a ring-shaped band that is clamped around the elongated structure part 2. In figures 1 and 2, several devices 3, 4 are mounted around the elongated structure part 2. There are two embodiments of the device 3, 4 shown in the drawings. These embodiments will be discussed in more detail later when discussing figures 3-6 and figures 7-9.

The devices and assembly of the devices and the wires as shown in the current drawings also have design features that can be part of a protection through a design or design patent.

The devices 3, 4 are mounted at a set mutual distance DI and hold several lines or wires 5 in place in a spiralling manner about the elongated structure part 2. In general, there will be at least three wires. In order to effectively function to reduce aerodynamic loads, and in particular reduce vortices, the thickness (indicated H) of the lines 5 and the pitch P are carefully selected with respect to the size of the cross section D of the elongated structure part 2, and which relates to the inner periphery 8 of the devices 3, 4. Thus, the lines 5 form several helices around the elongated structure part 2. The wires 5 are held functionally parallel with respect to one another, as can be seen in figure 2.

In order to hold the lines 5 at the right pitch, the devices 3, 4 have indents or grooves 9 that are at a predefined angle a with respect to a line L that is parallel to the axis R of the devices 3, 4 or the longitudinal axis of the elongated structure part 2. Furthermore, in order to clampingly hold the wires or lines 5, the size of the grooves or indents are adapted to the size of the lines 5. The angle a is indicated in figures 5/6 for device 3 and in figures 7/9 for device 4.

The device is shown in two different, exemplary embodiments. In a first embodiment, device 3 is further detailed in figures 3-6, and in a second embodiment device 4 is further illustrated in figures 7-9.

The device 3, 4 provides a ring around the elongated structure part 2, and has grooves or indents 9 for holding the line or wire 5 in place.

For the first embodiment, in figure 4 a perspective view is shown, in figure 5 an exploded view, and in figure 6 the rear part of the device of figure 5 is shown in detail.

In the first embodiment, the device 3 is provided with a casing 6 for holding a lighting element. Often, such a lighting element will be a Light Emitting Diode (LED), or similar light emitting device. The casing has a lid 12 that may have a window or even a lens. Here, the lid is attached via screws, making it relatively easy to apply and dismount. Alternatively, a snap coupling may be used. The casing 6 comprises grooves 13 for allowing a power line 7 to enter and leave the casing 6 of device 3. In figures 1, the power line 7 is at regular interspaces provided with lighting elements. These regular interspaces comply with the positions of casings of the device 3 of the first embodiment longitudinally along the elongated structure part 2.

A second, relatively more simplified embodiment of the device is shown in figures 7-9.

In figure 7 the second embodiment that is also shown in figures 1 and 2 is shown more detailed and in perspective view. In figure 8 the embodiment of figure 7 is depicted in top view, and in figure 9, the device of figure 8 is depicted in cross section as indicated.

The second embodiment of the device 4 provides a ring with an inner ring surface 8. The device 4 has an inner diameter D that usually is just a little smaller than the perimeter of the elongated structure part 2 in order to allow it to be firmly clamped on the elongated structure, just like the first embodiment device 3. The grooves or indents 9 are here in fact parts of the ring that bulge out radially outward. These are dimensioned for clamping or holding the wire or line 5 firmly. The groove 9 is here substantially cylindrical with an axis that is at an angle a with respect to a line parallel to the axis of the device 4. The angle a depends on the inner perimeter of the device.

In an embodiment, the vortex-reducing device is used to reduce vortices of elongated steel wire cables that have a diameter of about 84-86 mm. The rings in that embodiment have an inner perimeter that is about 0.3-0.6 mm smaller. In a particular embodiment, the vortex-reducing device is used to reduce vortices of elongated steel wire cables that have a diameter of about 85.67 mm. The rings in that embodiment have an inner perimeter of about 85.20 mm. The height of a ring is in that embodiment 25 mm. The diameter of the wires or lines H in that embodiment was selected about 8 mm. The hart-to-hart distance DI of the rings in the embodiment is about 127 mm. The pitch of the wires about the steel cable in that embodiment is about 762 mm. The angle a is here about 19-20°. The embodiment is designed to have an as low as possible aerodynamic drag difference in comparison to a circular cross section without these embodiments installed.

The vortex-reducing device is in general used for a structure part that has a diameter of between 50 - 250 mm. Usually as mentioned, the inner perimeter of the device will be a little smaller in order to allow proper clamping of the device around the structure part.

In general, as mentioned above, it was found that the line or wire 5 has a diameter of 0.07-0.13 times the diameter D of the elongated structure part. The line or wire 5 for use on a structure part having a diameter as details above extends a distance H of between 6-12 mm from the structure part, depending on the diameter of the structure part. In particular, as stated, the line or wire 5 has a diameter of 0.08-0.11 times the diameter D of the elongated structure part. Often, the line or wire will have a round or circular cross section. In such an embodiment, the wire or line for instance has a diameter of about 6-8 mm.

As stated before, the pitch is 6-13 times the main diameter of the structural part. In an embodiment as mentioned before, for a diameter D of the elongated structure of about 86 mm, the pitch of the wire is about 762 mm, thus resulting in an angle a of between 19° - 20°.

The lighting element may comprise several lighting devices which together allow making a desires color by switching lighting devices on and/or off, or by changing their intensity. In fact, when the assembly when provided with lighting elements is mounted onto a structure, it is possible, using a control device for controlling the individual lighting elements, to create an image from the assembly of lighting elements. It may even be possible, using the control device, to control each individual lighting element in such a way that the set of lighting elements together operate as pixels in a display device, allowing even projection of moving images, allowing display of a movie or part of a movie.

In an embodiment, the assembly is provided on a moving structure, like a Ferris wheel. When mounted on a Ferris wheel, the assembly can for instance be mounted on the spokes of the Ferris wheel. Then the control device is coupled to a measuring device for measuring a motion of the structure, for instance with the Ferris wheel measuring the rotational speed, the control device may take the motion into account and control the lighting devices in such a way that it compensates for the motion of the structure. Thus, in the example the control device is functionally coupled to the measuring device and to the lighting elements. Using the measurement values of the measuring device the control device can control the lighting elements on the structure in such a way so as to compensate for the motion of the structure. The control device can control the lighting elements in such a way that the lighting elements together project the visual illusion of a still image despite the motion of structure, or project the visual illusion of a movie or moving image despite the motion of the structure.

In an embodiment, the assembly comprises a series of devices 4 on one or more a structural parts of a structure, the devices provided with at least one lighting element, and a control device functionally coupled to the lighting elements of the devices. The control device provided with one or more images and with the positions of the lighting elements and with a data processor fur running a computer program which, when running on said data processor, calculates a lighting element illumination setting for the lighting elements such that the lighting elements together provide the visual illusion of the image. In an embodiment, the control device comprises a series of images and a time frame, thus representing a motion picture part, and said computer program when running calculates a time series of lighting element illumination settings for the lighting elements such that the lighting elements together provide a visual illusion of said motion picture part.

In an embodiment, the assembly further comprises a measuring device for measuring a motion of said structure, with said measuring device functionally coupled with said control device for providing motion data to said control device, and wherein said computer program, when running on said data processor calculates a dynamic position for the lighting devices using said motion data, and calculates said lighting element illumination settings using said dynamic positions.

It will also be clear that the above description and drawings are included to illustrate some embodiments of the invention, and not to limit the scope of protection.

Starting from this disclosure, many more embodiments will be evident to a skilled person. These embodiments are within the scope of protection and the essence of this invention and are obvious combinations of prior art techniques and the disclosure of this patent.

Claims (20)

Conclusions A vortex-reducing device for reducing the aerodynamic forces of air flows on an extending structural part with a The vortex reducing device according to claim 1, wherein the angle is such that the spiraling threads have a pitch of 6-13 times an inner diameter The vortex-reducing device according to claim 1 or 2, wherein the dimples are at an angle of 32 ° -12 °, in particular 30 ° -14 °. 20 The vortex-reducing device as claimed in one or more of the foregoing claims, wherein the dimples have a size for holding a wire with a diameter of between 0.07-0.13 times the inner diameter of the rings, in particular 0.8-0.11 times the inner diameter of the rings. 5. The vortex-reducing device as claimed in one or more of the foregoing claims, wherein the rings are mounted at a preset distance from each other for spirally angling the wires, the preset distance having a predetermined relationship to of the inner circumference. 5 comprising at least one lighting element, and the assembly further comprises a control device which is functionally coupled to the lighting elements of the devices. 5 longitudinal axis, the vortex-reducing device comprising rings for mounting around the extending structural part, each ring provided with a height, an inner circumference for clamping around the extending structural part, and comprising at least two indentations at an angle with respect to the longitudinal axis and which angle has a predetermined relationship to the inner circumference for holding wires in a predetermined spiraling manner on the extending structural member. The vortex-reducing device according to one or more of the preceding claims, wherein the rings are adapted to keep at least three spirals NL2018382 wires, in particular spiraling in a functionally parallel manner, forming a functionally multiple helix. The vortex-reducing device according to one or more of the preceding claims, wherein the ring has a functionally circular inner circumference, in particular the ring has an inner surface that functionally defines a circular cylinder part. The vortex-reducing device according to one or more of the preceding claims, wherein the rings have an inner diameter of between 20 and 250 mm. The vortex-reducing device according to one or more of the preceding claims, wherein the rings have an alignment identification for aligning the rings relative to each other. 10 further comprises one or more images, the positions of the lighting elements on the structure, and a data processing device for operating a computer program which, when operating on the data processor, calculates a lighting element setting for the lighting elements using the positions of the lighting elements such that the lighting elements together provide the visual illusion of the image. The vortex reducing device according to one or more of the preceding claims, wherein the rings are obtained by injection molding, in particular by injection molding of a polymeric material. The vortex-reducing device according to one or more of the preceding claims, wherein at least a part of the rings comprise a lighting element, in particular at least a part of the rings comprises a housing for one of the lighting elements. The vortex-reducing device as claimed in one or more of the foregoing claims, further comprising a power cable interconnecting the rings, in particular wherein the rings comprise a clamping part for holding the power line, the clamp providing the alignment identification. A vortex-reducing assembly comprising the vortex-reducing devices and wires for holding in a predetermined spiraling manner NL2018382 extending structure part. The vortex-reducing assembly of claim 13, wherein the extending structure is part of a structure, the device The vortex-reducing assembly according to claim 14, wherein the control device 15 of the rings. The vortex-reducing assembly of claim 15, wherein the control device comprises images and a timeline through which a moving image portion is represented, and the computer program when operating a time series of The lighting elements calculated using the positions of the lighting elements such that the lighting elements together provide a visual illusion of the moving image part. The vortex-reducing assembly of claim 16, wherein the assembly 25 further comprises a measuring device for a movement of the structure, wherein the measuring device is functionally coupled to the control device for supplying movement data to the control device, and wherein the computer program, when operating on the data processing device, calculates a dynamic position for the lighting elements below application of the motion data, and the lighting element calculates lighting settings using the dynamic positions to provide the visual NL2018382 illusion of the moving film part. A method for reducing aerodynamic forces of air flows on extending structure parts, in particular on cables and tubes, more particularly with a diameter of between 40 and 250 mm, wherein the vortex-reducing device according to one of the foregoing claims is mounted on an extending structural part, thereby spiraling the wires about the extending structural part. 19. A lighting assembly for mounting on an extending structural part of a structure, the assembly comprising a line comprising lighting elements spaced apart on the line, and devices for mounting on the extending structural part and the line holding on the structural part the devices comprising a ring for mounting around the structural part and the rings comprising a housing for one of the lighting elements. The lighting assembly of claim 19, further comprising a control device operatively coupled to the lighting elements or devices, wherein the control device comprises one or more images, the positions of the lighting elements on the structure, and a data processing device for operating a computer program that, when operating on the data processor, a lighting element lighting setting calculated for the lighting elements such that the lighting elements together provide the visual illusion of the image. -o-o-o-o-o2018382