Recirculating vertical wind tunnel

Abstract

A recirculating vertical wind tunnel for indoor skydiving having at least one recirculating airflow chamber. The airflow chamber comprises a first vertical member accommodating a flight chamber, a top horizontal member, a second vertical member, and a bottom horizontal member. The bottom horizontal member has a first section and a second section. A corner section connects the second section of the bottom horizontal member to the first vertical member. The second section of the bottom horizontal member contracts the airflow passing through the bottom horizontal member between the first section and the second section to the outlet of the corner section. The corner section further contracts the airflow leaving the second section of the bottom horizontal member toward the first vertical member.

Description

Technical Field

[0001] The present disclosure relates to recirculating vertical wind tunnels, and more particularly to wind tunnels used for indoor skydiving. Background Art

[0002] These wind tunnels recreate the experience of outdoor skydiving in a safe and controlled indoor environment. However, recirculating vertical wind tunnels are generally expensive to build and operate, and they require a large amount of space to generate airflow strong enough to suspend one or more people within acceptable noise and energy consumption levels, while also maintaining a constant airflow quality. It is generally desired that the airflow through the flight cabin is substantially uniform and has little turbulence. Moving along the direction of the airflow, a recirculating vertical wind tunnel generally includes a flight cabin, a diffuser located above the flight cabin, a first corner or turn, an upper horizontal air chamber, a second corner or turn, a vertical return air chamber, a third corner or turn, a lower horizontal air chamber, a fourth corner or turn, and an inlet constriction located below the flight cabin, the inlet constriction also being referred to as a converging duct or nozzle. The wind tunnel is designed to have a single flow path loop or multiple flow path loops. In the case of multiple flow path loops, the different airflow paths generally diverge downstream of the flight chamber (i.e., at or near the first corner) and then converge again upstream of the flight chamber (i.e., at or near the fourth corner).

[0003] Some recirculating vertical wind tunnel facilities install the bottom portion of the wind tunnel structure (e.g., bottom corner, lower horizontal air chamber, inlet contraction, lower portion of the vertical return air chamber) underground so that the flight cabin is located at or near ground level. In this way, the structural integrity of the wind tunnel can be increased while also avoiding the need to arrange the flight cabin on the upper layer of the facility, which can reduce commercial visibility / accessibility and increase related construction costs. This design approach can also allow the facility to meet local building height restrictions. In addition, arranging at least a portion of the flow path loop underground can help absorb heat and noise from the wind tunnel. However, due to the size requirements of many recirculating vertical wind tunnel designs, if the flight cabin will be located at or near ground level, a large amount of underground excavation is usually required to place the necessary foundation. For example, in some designs, the height between the base of the flight cabin and the base of the lower horizontal air chamber can be about 25 feet (7.6m) or more. Construction costs and engineering schedules will generally increase linearly with the length and width of the excavation, but increase exponentially with the depth of the excavation. Cost and time requirements may be further magnified depending on local soil composition and moisture content. Technical challenges also arise with increasing excavation depth, including consideration of the increased risk of collapse and water infiltration due to higher lateral pressures exerted by the surrounding terrain at greater depths. In addition, due to shallow bedrock in some locations, it may be difficult or costly to achieve the desired depth. When placing the structural foundation, traditional methods typically use poured cement to form the bottom portion of the wind tunnel to reduce construction costs, which typically results in simple geometric structures defining the flow path cross-section, compared to preformed structures with specially designed geometric structures produced from different materials. It is necessary for the recirculating vertical wind tunnel to have a reduced height between the flight cabin and the base of the flow path structure to minimize the impact on the quality of the airflow or wind tunnel efficiency for indoor skydiving.

[0004] In addition, wind tunnels usually have cable layer assemblies or structures to provide support for users standing in the flight chamber, while also allowing airflow to pass through during indoor skydiving to suspend users. In many wind tunnels, cables are installed to multiple welds arranged around the periphery of the flight chamber. The welds are usually supported by separate load-bearing beams or other elements of the facility structure, which can increase construction costs. The cables usually have varying sizes to minimize the horizontal footprint required for the welds around the flight chamber, because the cross-sections of many flight chambers are circular or substantially circular, meaning that the cables passing through the edge of the flight chamber do not need to be as long as the cables passing through the center diameter of the flight chamber. The welds usually have removable top covers to access the ends of the cables firmly mounted in the welds. Therefore, this design is usually installed, replaced and maintained from above by workers on the commercial floor of the facility (such as the assembly cabin or observation area around the flight chamber). Since the cables extend across the flight chamber and are installed in the welds, the interior of the welds is usually aerodynamically connected to the wind tunnel flow path. In order to prevent noise from penetrating into the commercial area around the flight chamber through the welds, the top covers are usually sealed to prevent customers from being exposed to high decibel levels in the wind tunnel. This design has relatively expensive component construction costs; a subjectively poorer aesthetic appearance due to visible access covers around the flight chamber; a relatively long, complex and laborious installation / maintenance process, which increases labor costs and engineering timelines; and a limited range of possible suppliers due to the complexity of the requirements.

[0005] Another consideration in wind tunnel design and construction is the horizontal dimensional requirements of the flow path. For example, some locations may not have the space or footprint needed to accommodate the horizontal length dimensional requirements of a particular wind tunnel design. In this sense, fewer locations are available for wind tunnel construction. It is desirable for a recirculating vertical wind tunnel to have reduced dimensional requirements along the length of the flow path structure.

[0006] The above discussion of the prior art and any limitations thereof is intended to be illustrative and not exclusive. Other limitations of the prior art will become apparent to those skilled in the art upon reading the specification and drawings. Summary of the invention

[0007] The following embodiments and aspects thereof are described and illustrated in conjunction with systems, tools and methods, which are intended to be illustrative rather than limiting in scope. In various embodiments, one or more of the described problems are reduced or eliminated, while other embodiments involve other improvements.

[0008] The present disclosure relates to a recirculating vertical wind tunnel design. One aspect is to reduce the vertical distance or height between the base of the flight chamber and the base of the fourth corner and / or the lower horizontal air chamber. Another aspect is to merge the inlet constriction and the fourth corner into a single structure and airflow path element below the flight chamber. Another aspect is to reduce the construction costs and time requirements associated with the depth of the drill when the flight chamber is arranged at or near ground level. Another aspect is efficient energy consumption to reduce the operating costs of the wind tunnel. Another aspect is to minimize turbulence, friction and pressure losses within such a wind tunnel. Another aspect is to provide an airflow within the flight chamber that is at least comparable to the quality of existing wind tunnel designs in terms of uniformity and turbulence.

[0009] These aspects can be met by a vertical wind tunnel for indoor skydiving comprising:

[0010] at least one recirculating airflow plenum, the airflow plenum comprising a first vertical member, a top horizontal member, a second vertical member, and a bottom horizontal member;

[0011] means for providing an airflow through the airflow plenum and in an upward direction within the first vertical member;

[0012] a flight chamber housed within the first vertical member of the airflow plenum;

[0013] A corner section connects the bottom horizontal member to the first vertical member;

[0014] wherein the bottom horizontal member has a first section and a second section, the first section and the second section extend from the second vertical member to the first vertical member, the first section is connected to the second vertical member, the second section is connected to the corner section, and the corner section connects the bottom horizontal member to the first vertical member;

[0015] The second section of the bottom horizontal member causes airflow passing through the bottom horizontal member to contract between the first section and the second section to the outlet of the corner section;

[0016] The corner section further constricts airflow exiting the second section of the bottom horizontal member toward the first vertical member.

[0017] By providing a corner section, which connects at least one bottom horizontal member to the first vertical member and its flight chamber, the overall height of such a vertical wind tunnel can be significantly reduced by providing a corner section that contracts the airflow passing through the corner section. The necessary inlet contraction upstream of the flight chamber is then provided by the corner section. Therefore, compared to such wind tunnels of the prior art, the bottom of the flight chamber can be arranged much lower. Therefore, the bottom of the flight chamber can be arranged at the very bottom of the first vertical member. In order to provide a balanced airflow contraction, the vertical wind tunnel provides a two-stage contraction, which does not necessarily need to be separated from each other, but can be performed continuously. A contraction zone is arranged in the corner section at the bottom of the first vertical member, and the upstream contraction section is arranged in the bottom horizontal member.

[0018] It is believed that this is the first time that the use of a first vertical member and its corner section at the bottom of the flight chamber is proposed as an inlet constrictor.

[0019] The benefits of the present disclosure can be achieved with a wind tunnel having a single return airflow plenum or having more than one return airflow plenum, such as two airflow plenums arranged in relation to the first vertical member on opposite sides of the first vertical member. Furthermore, the benefits of the present disclosure can be achieved regardless of where the means for providing airflow, the fan assembly, is arranged in the return airflow plenum. The fan assembly can be arranged in the top horizontal member. It is also possible to arrange the fan assembly in the second vertical member, particularly in the upper section of the second vertical member.

[0020] In order to reduce the turbulence in the contracted corner section, a set of guide vanes can be arranged in the corner section, which redirects the airflow entering the corner section in a horizontal flow into the direction of the flight chamber in the first vertical member. According to the guide length provided by the guide vanes to the airflow, the guide vanes that are shorter in the direction of the airflow can be arranged in the corner section. Depending on the wind tunnel configuration, two or more sets of guide vanes can also be used. The guide vanes can be arranged in a portion of the corner section that is similar to an arch, which usually provides a part of the air chamber wall. The arch portion is preferably curved along a curved direction that redirects the airflow in the corner section.

[0021] In some embodiments, another measure to redirect and contract the airflow in the corner section while reducing turbulence is to provide a ridge in the bottom section. The ridge acts similar to a guide vane, redirecting the flow of at least the lower part of the airflow entering the corner section. In the case where the wind tunnel has two return airflow chambers arranged relative to each other with respect to the first vertical member, the two ridges can generally be arranged with their backs adjacent to each other and arranged to be aligned with the vertical centerline of the flight chamber passing through the first vertical member. This means that the two ridges are arranged so that their centers are projected in the middle of the flight chamber. The two ridges can be provided as separate components by a single component, or, for example, formed integrally in the air chamber wall at this position.

[0022] Many further aspects of the wind tunnel are disclosed below. All features disclosed and described in a particular embodiment may also be used independently of each other. This means that even if an individual feature and the benefits of each feature are described together with other features, the other features disclosed in combination with that feature are not necessarily required to achieve the benefits of the individual feature and each feature.

[0023] Another aspect is to provide a cable layer assembly or structure that reduces the manufacturing cost of the components used for assembly. Another aspect is to provide a cable layer assembly that reduces the construction cost of larger wind tunnel facility buildings. Another aspect is to simplify and reduce the time required for installation of the cable layer assembly. Another aspect is to simplify and reduce the time required for maintenance of the cable layer assembly. Another aspect is to reduce the time to market for new wind tunnel buildings with such cable layer assemblies. Another aspect is to increase the source of potential suppliers for cable layer assemblies. Another aspect is to provide a cable layer assembly that can streamline the floor surrounding the flight cabin or make it simple and abstract. Another aspect is to provide a cable layer assembly that is configured to be serviced from below.

[0024] Another aspect is to provide a stepped air chamber bifurcation in the corners of the wind tunnel to reduce the size requirements between the corners of the wind tunnel. Another aspect is to provide a stepped air chamber bifurcation in the corners of the wind tunnel to provide sufficient space gap to accommodate ducts and / or duct fans arranged directly downstream of the corner. Another aspect is to provide a stepped air chamber bifurcation in the corners of the wind tunnel to provide sufficient space gap to accommodate other structural elements such as support columns or beams.

[0025] Another aspect is to provide a recirculating vertical wind tunnel wherein the airflow plenum is divided in the vertical return member.

[0026] Another aspect is to provide a recirculating vertical wind tunnel having a flyer exchange system for controlling participant movement, and environmental exchange between the flight chamber and an ambient observation area of ​​the facility.

[0027] In addition to the embodiments and aspects described above, further embodiments and aspects will become apparent by reference to the detailed description and accompanying drawings, which constitute a part of this specification. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Hereinafter, the present disclosure is described with reference to the following drawings:

[0029] Figure 1 shows a side view of a recirculating vertical wind tunnel according to the prior art;

[0030] Figure 1A Shows a cross-sectional view taken along line AA Figure 1 A cross-sectional view of a wind tunnel;

[0031] Figure 2 shows a perspective view of a recirculating vertical wind tunnel according to the present disclosure;

[0032] Figure 3 Shows Figure 2 Front and side view of the wind tunnel;

[0033] Figure 4 Shows Figure 2 Right side view of the wind tunnel;

[0034] Figure 5 Shows Figure 2 Bottom view of the wind tunnel;

[0035] Figure 6 Shown along Figure 3 The line 6-6 intercepts Figure 2 Top cross-section of the wind tunnel;

[0036] Figure 7 Shown along Figure 6 The line 7-7 is intercepted, Figure 2 A partial cross-sectional side view of a fourth corner of the wind tunnel;

[0037] Figure 8 Shown along Figure 6 The line 8-8 is intercepted, Figure 2 A partial cross-sectional side view of a fourth corner of the wind tunnel;

[0038] Fig. 9 shows a partial perspective view of the lower horizontal air chamber of the wind tunnel;

[0039] Fig.10 Shows Fig. 9 A side view of the lower horizontal air chamber;

[0040] Fig.11 Shows Fig.10A cross-sectional view taken along line 11-11;

[0041] Fig.12 Shows Fig.11 A cross-sectional view taken along line 12-12;

[0042] Fig.13 shows an exploded perspective view of another embodiment including a guide vane structure;

[0043] Fig.14 Shows Fig.13 A side view of a guide blade structure;

[0044] Fig.15 Shown through Fig.14 A cross-sectional view taken from the center of the base of the guide blade structure in the frame B region;

[0045] Fig.16 shows a perspective view of another embodiment including a cable layer assembly;

[0046] Fig.17 Shows Fig.16 A top view of

[0047] Fig.18 Shows Fig.16 A perspective view of one of the welded parts of the cable layer assembly;

[0048] Fig.19 Shows Fig.18 Exploded view of;

[0049] Fig. 20 Shows Fig.16 A bottom view of a cable layer assembly;

[0050] Fig.21 Shows Fig. 20 Detail view of box C when partially cut away;

[0051] Fig. 22 Shown along Fig.17 A cross-sectional view taken along line 22-22 of ;

[0052] Fig.23 Shows Fig. 22 Detail view of box D;

[0053] Fig.24 Shows Fig.23 A wider perspective of

[0054] Fig.25 shows a side view of a single return recirculation wind tunnel having a stepped corner configuration;

[0055] Fig.26A partial side view of the dual return recirculation wind tunnel and stepped corner configuration is shown;

[0056] Fig. 27 shows a perspective view of a single return recirculation wind tunnel with a converging corner;

[0057] Fig.28 Shows Fig. 27 Another perspective of the wind tunnel;

[0058] Fig.29 shows a perspective view of another embodiment of a recirculation wind tunnel with a separate return air tower;

[0059] Fig.30 Shows Fig.29 Side view of the wind tunnel;

[0060] Fig.31 shows a schematic floor plan of a wind tunnel facility having a flyer exchange device according to the present disclosure;

[0061] Fig.32 A side perspective view of the flyer exchange device is shown;

[0062] Fig.33 shows a side view of a recirculating vertical wind tunnel with a flyer exchange system according to the present disclosure;

[0063] Fig.34 Shown along Fig.33 A cross-sectional view taken along line 34-34;

[0064] Fig.35 Shown along Fig.33 A cross-sectional view taken along line 35-35.

[0065] exist Figure 6 , Figure 7 , Fig.34 and Fig.35 In a cross-section view of a wind tunnel, the internal wind tunnel space is usually indicated by diagonal hatching.

[0066] Before further explaining the depicted embodiments, it should be understood that at the time of the present application, the present invention is not limited to the details of the particular arrangement shown, as the present invention is capable of other embodiments. It is intended that the embodiments and drawings disclosed herein be considered illustrative rather than restrictive. In addition, the terms used herein are for descriptive purposes and not as limitations. DETAILED DESCRIPTION

[0067] Figure 1 and Figure 1AA recirculating vertical wind tunnel 100 according to the prior art is shown. Moving along the direction of airflow, the wind tunnel 100 includes a flight cabin 101, a diffuser 102 located above the flight cabin 101, a first corner 103, an upper horizontal plenum 104, a second corner 105, a vertical return plenum 106, a third corner 107, a lower horizontal plenum 108, a fourth corner 109, and an inlet constriction 110 located below the flight cabin 101. The lower horizontal plenum 108 has a first section 111 and a second section 112, the second section 112 having a constricted cross-section. One or more fans (not shown) are arranged in the flow path plenum to generate an airflow through the flow path plenum. In Figure 1 The direction of the airflow is indicated by the dashed arrows. Guide vanes 113 are arranged in the corners 103, 105, 107, 109 to redirect the airflow between the diffuser 102 and the upper horizontal plenum 104, the airflow between the upper horizontal plenum 104 and the vertical return plenum 106, the airflow between the vertical return plenum 106 and the lower horizontal plenum 108, and the airflow between the lower horizontal plenum 108 and the inlet constriction 110, respectively. Figure 1 The position of the middle guide vane structure 113 is indicated by a dotted line. Before the airflow enters the flight chamber 101 to support the user for indoor skydiving, the speed of the airflow is increased by the reduced cross-section of the second section 112 of the lower horizontal air chamber 108 and the inlet constriction 110. A vertical wind tunnel may be provided with a single flow path loop or multiple flow path loops. In a wind tunnel with two or more return loops, the different airflow paths typically diverge at or near the first corner 103 above the flight chamber 101, and converge at or near the fourth corner 109 below the flight chamber 101. Multi-path wind tunnels are usually designed symmetrically. Although usually more expensive to build than a flight chamber with a rectangular cross section, a flight chamber with a circular or substantially circular cross section typically has a more uniform and less turbulent airflow because the hard corners (sharp corners) of the rectangular cross section generate turbulence. Similarly, the four corners of the inlet constriction 110 also introduce turbulence into the airflow entering the flight chamber 101.

[0068] Figures 2 to 8One possible embodiment of a recirculating vertical wind tunnel 200 according to the present disclosure is shown. Moving along the airflow direction, the wind tunnel 200 includes a flight cabin 201, a diffuser 202 located above the flight cabin 201, a first corner 203, an upper horizontal air chamber 204, a second corner 205, a vertical return air chamber 206, a third corner 207, a lower horizontal air chamber 208, and a fourth corner 209 (a contraction corner). The wind tunnel 200 has two symmetrical airflow return paths that diverge at the first corner 203 and converge at the fourth corner 209. For purposes of convenience and brevity, the description below generally only refers to a single side or a single loop of the wind tunnel 200; it is understood that unless otherwise noted, the structure of both sides of the wind tunnel 200 is the same. In other embodiments, the wind tunnel 200 may include a single return airflow path (see Fig. 27 and Fig.28 ) or more than two return airflow paths (not shown). Fig. 27 and Fig.28 The single return recirculation vertical wind tunnel is Figures 2 to 8 The double return wind tunnel 200 is designed in the same principle as the wind tunnel 200 of the present invention, and therefore will not be described in further detail herein. The upper horizontal air chamber 204 has two ducted fans 210, which generate airflow through the wind tunnel 200. Other embodiments have one fan 210 or more than two fans 210. In addition, the fan 210 may also be located at other locations along the flow path loop, including locations that are not in the upper horizontal air chamber 204. In addition, multiple fans 210 may be arranged in a single air chamber, rather than being arranged in separate air chambers as shown. The spirit and scope of the present disclosure are not so limited. Based on simulations, it is demonstrated that the double return wind tunnel 200 achieves airflow quality (for indoor skydiving purposes) comparable to existing wind tunnel designs in the flight chamber 201, such as in terms of turbulence, shear, and velocity diagram uniformity.

[0069] The third corner 207 may have a relatively wide rectangular configuration to reduce the excavation depth. For example, if the cross-section of the third corner 207 at the junction with the lower horizontal air chamber 208 is more square, the height of the third corner 207 along the vertical dimension needs to be increased to keep the cross-sectional area through the third corner the same, in order to reduce air flow friction. By horizontally widening the third corner 207, the lateral space requirement of the base is increased while the depth requirement is reduced, which enables the excavation cost to be purely saved if the flight cabin is arranged at or near the ground level. At the junction of the vertical return air chamber 206 and the third corner 207, the vertical return air chamber 206 can share the widened geometry of the third corner 207. Similarly, at the junction of the lower horizontal air chamber 208 and the third corner 207, the lower horizontal air chamber 208 can also share the widened geometry of the third corner 207.

[0070] The lower horizontal air chamber 208 may include a first section 211 and a second section 212. Along the airflow direction, the vertical return air chamber 206 transitions through the third corner 207 and enters the first section 211 of the lower horizontal air chamber 208. Then, it transitions through the first section 211 and enters the second section 212 of the lower horizontal air chamber 208. The second section 212 is connected to the fourth corner 209 (retracted corner) located below the flight chamber 201. In the case where the vertical return air chamber 206 and / or the third corner 207 have a rectangular cross section, the first section 211 of the lower horizontal air chamber 208 may also have a substantially rectangular cross section. Of course, the vertical return air chamber 206, the third corner 207, and the lower horizontal air chamber 208 may have different geometric structures other than rectangular, including other polygonal geometric structures or curved geometric structures (e.g., circular, elliptical or substantially circular, substantially elliptical) and different combinations thereof. Flat walls forming rectangular geometries are often used at these locations of the flow path to reduce construction cost and complexity, whereas curved or multi-sided geometries often increase construction cost and complexity when used, and even hard corners can introduce additional turbulence into the airflow.

[0071] The first section 211 of the lower horizontal plenum 208 may include a corner transition portion 213 for transitioning into the second section 212 of the lower horizontal plenum 208. For example, in the depicted embodiment, at the junction between the first section 211 and the second section 212, the cross-section of the flow path is generally rectangular with rounded top corners. The upper corner of the first section 211 gradually transitions to such rounded corners at the second section 212 through the corner transition portion 213 between the hard corners near the third corner 207. In some embodiments, the corner transition portion 213 may extend at least along a majority of the longitudinal length of the first section 211. In other embodiments, the corner transition portion 213 may extend at least along two-thirds of the longitudinal length of the first section 211. Further, in some embodiments, the corner transition portion 213 may extend at least along three-quarters of the length of the first section 211, including along the entire longitudinal length of the first section 211 or substantially the entire longitudinal length. Corner transition portion 213 helps reduce turbulence downstream of the upper corner of second section 212 .

[0072] When viewed along the longitudinal axis, the second section 212 of the lower horizontal air chamber 208 tapers from a substantially rectangular cross-section with rounded corners at the junction with the first section 211 to a substantially semi-oval or semi-elliptical cross-section at the junction with the fourth corner 209 (see FIG. Figure 7). Other descriptive terms for the shape of the cross section may include half a stadium, tunnel, rainbow, etc., referring to a flat or substantially flat bottom / base side bounded by an arch. Between the first section 211 and the fourth corner 209, the flow path cross section of the second section 212 shrinks in vertical and horizontal dimensions. This geometric structure shrinkage increases the speed of the airflow entering the fourth corner 209. The smooth transition of the cross-sectional geometry when shrinking along the longitudinal length of the second section 212 (between the first section 211 and the fourth corner 209) also promotes airflow with less turbulence during the acceleration of the airflow through the geometric structure. In addition, this contraction of the second section 212 allows the flow path cross section to smoothly transition to and through the fourth corner 209. The substantially semi-oval or substantially semi-elliptical cross-sectional geometry of the second section 212 at the fourth corner 209 facilitates forming a substantially circular horizontal cross-section of the rising airflow at the outlet of the fourth corner 209 below the flight cabin 201 once it passes through the fourth corner 209 and turns to the horizontal plane, which allows for a shorter contraction with less turbulence.

[0073] The fourth corner 209 (contraction corner) turns the airflow in the lower horizontal air chamber 208 directly upward and enters the flight chamber 201. At the same time, the fourth corner 209 (contraction corner) also reduces the total cross-sectional area of ​​the flow path between the lower horizontal air chamber 208 and the base of the flight chamber 201, which increases the speed of the airflow that suspends the user in the flight chamber 201. In an embodiment with two or more return loops, the fourth corner 209 (contraction corner) also merges the separate airflows before they enter the flight chamber 201. By integrating the fourth corner and the inlet constriction together in a single structure, the need for a separate inlet constriction structure below the flight chamber is eliminated. In this way, the vertical distance between the base of the flight chamber 201 and the fourth corner 209 (contraction corner) and / or the base of the lower horizontal air chamber 208 can be significantly reduced.

[0074] For example, the height of the wind tunnel flow path between the base of the flight chamber 201 and the base of the fourth corner 209 (the contraction corner) can be reduced by approximately 35% compared to comparable wind tunnel designs, but without significantly sacrificing efficiency. This can correspond to a height of approximately 10 feet or more. The height savings also correspond to a shortening of the entire wind tunnel flow path. With the disclosed design, construction with reduced excavation and even construction entirely above ground is feasible. Benefits include construction cost savings, construction time savings, and reduced construction risk. In addition, the reduced height requirements enable construction at locations with height restrictions.

[0075] Specifically, in some embodiments, for a dual-circuit recirculation wind tunnel, the height between the base of the flight chamber 201 and the base of the fourth corner (retraction corner) 209 (or the lower horizontal air chamber 208) may be implemented to be less than or equal to 1.3 times the diameter of the flight chamber 201. In other words, [the vertical distance between the base of the flight chamber and the base of the retraction corner] ≤ [1.3×the diameter of the flight chamber]. In some embodiments, for a single-circuit recirculation wind tunnel, the height between the base of the flight chamber 201 and the base of the fourth corner (retraction corner) 209 (or the lower horizontal air chamber 208) may be implemented to be less than or equal to the product of the diameter of the flight chamber 201 and a factor of 1.9. In other words, [the vertical distance between the base of the flight chamber and the base of the retraction corner] ≤ [1.9×the diameter of the flight chamber].

[0076] With regard to costs and therefore potential savings, it should be recognized that the cost of building a wind tunnel depends on the location. Factors include the cost of wind tunnel materials, labor costs, the cost of transporting materials to the location, the cost of earthwork at a particular location, etc. Factors may also vary depending on quality and availability. Time in both engineering schedules and market forces may further affect costs. In other words, each project has its own challenges and circumstances, making it difficult to make direct comparisons with completed wind tunnel sites. Based on available data and engineering estimates, a wind tunnel according to the present disclosure may save approximately $20,000 to $100,000 per foot of excavation, with an estimated average saving of approximately $40,000. This makes each building associated with up to $400,000 or more. Some projects may achieve savings of $1,000,000 or more. These savings may compensate for the increased costs in other areas, if any, such as specialized manufacturing, transportation, or use of relatively more expensive materials. Leaving aside the excavation depth, it may seem counter-intuitive that the complex geometry and curvature of a contracting corner according to the present disclosure can save costs compared to a more basic geometry (e.g., a rectangular corner made of poured concrete). However, once a mold is built for a curved wall plenum (e.g., lower horizontal plenum section 212), which can be reused for future projects with the same pattern, actual cost savings can be achieved compared to poured concrete. For example, using a preformed fiberglass plenum with a complex curvature can yield savings of up to $100,000 in component and installation costs compared to poured concrete for a simple plenum geometry (e.g., a flat wall), which offsets the potential increase in shipping and material costs. By reducing the height, concrete (Construction Specification Institute (CSI) 2012 Division Code 03) and earthwork (CSI 2012 Division Code 31) costs can be significantly reduced, in the hundreds of thousands of dollars. Depending on the wind tunnel site, significant savings can be achieved in earthwork in particular, as site moisture, soil type, bedrock depth, etc. can significantly increase excavation costs and required support costs, in some cases increasing total costs by more than $1,000,000 for particularly challenging construction sites. In addition, according to the present disclosure, it is estimated that the average project schedule is reduced by one or two months. Some of the time savings cannot be understood in relation to keeping project costs down and accelerating payback by opening a wind tunnel facility. Again, it must be recognized that each construction project is unique and depends on the interaction of multiple factors; meaning that it is impossible to achieve the potential savings escaped herein in every case. However, limited data and cash estimates indicate that, generally regardless of the specific project site, significant savings are expected when constructing a wind tunnel with a reduced corner design according to the present disclosure.

[0077] The fourth corner 209 (the contracting corner) includes a smooth or substantially smooth curvature during the transition of the air chamber wall. This configuration also reduces turbulence past the fourth corner 209 (the contracting corner). In a double return or double circuit wind tunnel design (see Figures 2 to 8 ), the fourth corner 209 (the contraction corner) can be described as including two curved arches 214. The bottom surfaces of each lower horizontal air chamber 208 are joined to form a centerline 215 at one end of the fourth corner 209 (the contraction corner) along the transverse axis of the wind tunnel 200. The centerline 215 can then be considered to form the base of the fourth corner 209 (the contraction corner). Each arch 214 of the fourth corner 209 (the contraction corner) spans over the ends of the centerline 215 that are inclined away from each other to define the cross-sectional geometry of the flow path at the transition of the air chamber wall between the second section 212 of each lower horizontal air chamber 208 to the flight chamber 201. In this manner, the arches 214 form a V-shape that is squared by the transverse axis of the wind tunnel 200, with the centerline 215 formed at the lowest point or base midpoint of the V-shape (see Figure 8 ). Each dome 214 is located at a location where the tube structure of the fourth corner 209 (the contraction corner) joins the tube structure of the lower horizontal air chamber 208. However, it should be recognized that the dome 214 itself need not be formed by a separate structure along the transition portion of the air chamber wall. For example, the fourth corner 209 (the contraction corner) and at least a portion of the lower horizontal air chamber 208 can also be formed as a single piece. The dome 214 is described as a point in space along the air chamber transition, and is not necessarily formed by a separate structure at the physical junction between the air chamber segments or is arranged as a separate structure. Similarly, any description herein between "corner" and "air chamber" is for convenience of description, and the flow path structure of the wind tunnel 200 can be joined at different locations.

[0078] In addition, in the depicted embodiment, the centerline 215 constitutes a ridge. Here, the ridge is formed by the bottom surface of each lower horizontal air chamber 208, which turns upward to converge at the centerline 215. In other embodiments, the ridge may be formed by one or more components installed in this position (for example, if the bottom surface of the lower horizontal air chamber 208 is flat or substantially flat, it does not turn upward to form a ridge itself). At least compared to the embodiment that does not have an upwardly protruding ridge structure so that the airflow along the bottom surface can converge head-on, the ridge helps to redirect the airflow along the bottom surface of each lower horizontal air chamber 208 upward into the fourth corner 209 (contraction corner) and reduce the turbulence generated from the fusion of the airflow. However, it should be recognized that the ridge is not completely required to achieve the benefits of the present disclosure. In fact, the ridge may not exist in other embodiments. In this case, the centerline 215 (the lowest point or base midpoint of the above-mentioned V-shape) can be set to a flat or substantially flat surface. For example, the bottom surface of the lower horizontal air chamber 208 may be joined in a flat or substantially flat manner at the centerline location, or, depending on the specific configuration, the centerline 215 may be located along the surface of a single air chamber component at this location. In a single return embodiment, the centerline 215 may be disposed at a location where the bottom surface of the lower horizontal air chamber 208 joins the vertical or substantially vertical end wall of the fourth corner 209 (the contraction corner), for example, at a hard edge or through a curved surface transition. Thus, similar to the dome 214, the centerline 215 is described as a point in space.

[0079] Nevertheless, using these conventions, the fourth corner 209 (the converging corner) smoothly transitions from the circular base of the flight chamber 201 to a point along one of the domes 214. The smooth transition of the plenum wall at the fourth corner 209 (the converging corner) comprises a single curvature or substantially a single curvature (see FIG. 1 ) as it moves along the horizontal axis of the lower horizontal plenum 208 between the base of the flight chamber 201 and the apex of each respective dome 214. Figure 8 ); other embodiments may include a slightly S-shaped double curvature profile. Along a transverse axis perpendicular to the longitudinal axis in a horizontal plane, the smooth transition of the wall of the fourth corner 209 (the pinch corner) includes an S-shaped double curvature profile (see Figure 7 ). The walls of the fourth corner 209 (contraction corner) do not include any hard corners; transitions are achieved through curves so that all surfaces are smooth. This promotes aerodynamic efficiency while minimizing turbulence. When approaching the fourth corner 209 (contraction corner), the cross-section of the second section 212 of the lower horizontal air chamber 208 can be semi-elliptical, so that each inclined arch 214 defines the top wall and side walls of the lower horizontal air chamber 208 at its junction with the fourth corner 209 (contraction corner). The base of the lower horizontal air chamber 208 can be flat, substantially flat, or curved, as described below.

[0080] The bottom surface 216 (floor) of the lower horizontal plenum 208, or the lower horizontal plenum 208 and the third corner 207 and / or the fourth corner 209, may be configured to drain any liquid that may accumulate in the wind tunnel 200. For example, Figures 3 to 5 As shown, the entire bottom surface or substantially the entire bottom surface 216 on each side of the fourth corner 209 may be bowl-shaped. The lowest point 217 of each bowl-shaped bottom surface 216 may be provided with a drainage hole. In some embodiments, the lowest point 217 of the bottom surface 216 (floor) may be located along the central longitudinal axis passing through the lower horizontal air chamber 208, at the junction between the first section 211 and the second section 212 (see FIG. Figure 5 ). In this manner, the bottom surface 216 (floor) "drops" along the longitudinal axis in and after the third corner 207, which can help accommodate the change in direction of the airflow passing through the third corner 207 into the lower horizontal air chamber 208. Therefore, the bottom surface 216 (floor) "rises" along the longitudinal axis when moving through the second section 212 between the first section 211 and the fourth corner 209 (the contraction corner), which can coincide with the contraction of the flow path in the second section 212. Similarly, along the transverse axis, the bowl shape of the bottom surface 216 (floor) can further reduce turbulence through the bottom surface 216 (floor). The vertical depth of the bottom surface 216 (floor) along the perimeter of the bowl shape is reduced, which can further provide for saved excavation. To this end, in some embodiments, the base of the third corner 207 can be arranged higher than the base of the fourth corner 209 in the vertical direction. A pump can be provided to assist in draining the accumulated liquid.

[0081] Fig. 9 Another embodiment of a lower horizontal air chamber 208 is shown including a first section 211 (partial view) and a second section 212. In this embodiment, the second section 212 has a two-piece construction including a contraction portion 218 connected to the first section 211 and a transition portion 219 of constant cross-sectional area connected to the fourth corner 209 (contraction corner). In addition, the bottom surface 216 (floor) of the lower horizontal air chamber 208 that completes the closed flow path of the airflow is provided separately from the air chamber wall structure. For example, the bottom surface 216 (floor) can be concrete to reduce costs, while the wall structure can be fiberglass or other materials manufactured into a specific shape, which generally increases costs. This is another example of how the flow path structure described herein can be alternatively constructed and assembled within the spirit and scope of the present disclosure. Similarly, the transition portion 219 is characterized by being part of the lower horizontal air chamber 208 or part of the fourth corner 209 (contraction corner). As in the depicted embodiment, the first section 211 can be amorphous to form a corner transition portion 213. Conversely, as Figures 10 to 12As seen in FIG. 2 , the corner transition portion 213 can be a separate structure (e.g., a plate) mounted within the air chamber of the first section 211. In this manner, the first section 211 can be configured with flat or substantially flat walls to reduce costs. The corner transition portion 213 defines the cross-section of the flow path through the first section 211 at the corner. The corner transition portion 213 can be shaped to smoothly contract the cross-section of the flow path as it moves between a hard corner near the third corner 207 to a rounded or substantially rounded corner at the junction with the second section 212.

[0082] Fig.13 and Fig.14 Another embodiment is shown, in which the rounded arch 214 of the fourth corner 209 (the contracting corner) corresponds to a frame structure 220 including a plurality of guide vanes 221. In the depicted embodiment, each side of the frame structure 220 is laterally connected to the transition portion 219 of the second section 212, but the lower horizontal air chamber 208 may also have other configurations. Above, the frame structure 220 is connected to the fourth corner 209 (the contracting corner). The guide vanes 221 are configured to redirect the airflow upward toward the flight chamber 201. The guide vanes 221 and therefore the rounded arch 214 may be arranged at a certain angle to the horizontal plane. As shown in FIG. Fig.14 As seen in the depicted embodiment, the arch 214 can be inclined at, for example, approximately 45°. Fig.15 , centerline 215 corresponds to a ridge in the depicted embodiment, which may be provided by a separate structure (e.g., a plate) adjacent to the plenum floor. As described above, the ridge may be omitted in some embodiments; although the ridge member improves flow uniformity through the center of the flight chamber by turning the airflow along the bottom surface of the plenum 208 upward in the manner of guide vanes, it is not entirely required to achieve all of the benefits of the present disclosure described herein. The guide vanes 221 may be hollow or include channels to allow cooling fluid to flow through the guide vanes 221, thereby removing frictional heat generated from the recirculated airflow. The frame structure 220 may provide structural support to the fourth corner 209 (the converging corner), and therefore to the components of the wind tunnel 200 mounted above the fourth corner 209 (the converging corner). Thus, the frame structure 220 may be load-bearing and securely mounted in the floor adjacent to the wind tunnel plenum. Of course, other structures (e.g., building support beams) may also provide structural support to the wind tunnel components, in which case, depending on the design, the frame structure 220 does not need to be load-bearing.

[0083] Now go to Figures 16 to 25 In a further embodiment, the wind tunnel 200 further includes a cable layer assembly 222. Figures 13 to 15In an embodiment, the cable layer assembly 222 can be mounted to the frame structure 220. In this manner, the cable layer assembly 222 is supported as a whole by the wind tunnel 200 structure, which eliminates the need to provide a separate load-bearing element to support the cable layer assembly 222, thereby reducing the construction cost of the wind tunnel facility. The cable layer assembly 222 includes a plurality of cables 223 that form a floor in the flight chamber 201, on which a user can stand and through which airflow can pass to suspend the user. The cable layer assembly 222 also includes a plurality of shells or weldments 224 surrounding the periphery of the flight chamber 201. Now referring to Fig.18 and Fig.19 Each weldment 224 may have: a mounting plate 225 for firmly mounting the end of the cable 223 on the mounting plate 225; a fairing 226, forming a portion of the airflow chamber wall at the junction of the flight cabin 201 and the fourth corner 209 (contraction corner) (see Fig.23 and Fig.24 ); and a cover plate 227 provided on a floor surface adjacent to the flight chamber 201 at the observation level of the wind tunnel facility. The cover plate may be configured to mount a panel 228 forming a wall of the flight chamber 201.

[0084] like Fig.21 Seen in ( Fig.21 223 are arranged in a square or substantially square outline pattern across the base of the flight chamber 201. In this way, cable production and replacement costs can be reduced because a single cable specification is used for the entire floor. This can also increase the source of suitable suppliers for the cables 223. Each cable 223 is attached to an eyebolt 229. The eyebolt 229 extends through the mounting plate 225 of the corresponding weldment 224 to be compressed by being attached to the compression spring 230 through the nut 231 and the washer 232 (but other connecting components can also be accommodated). The sleeve 233 can reduce the wear of the eyebolt 229 and maintain the coaxiality of the eyebolt 229. Therefore, each cable 223 is maintained in tension across the flight chamber 201 and is configured to flexibly absorb forces (e.g., forces from a falling user to prevent injury) through the compression spring 230. With this mounting configuration, the cable 223 itself can be easily replaced if necessary without having to remove other components from the mounting plate 225.

[0085] like Fig.23 and Fig.24As seen in FIG. 2 , the fairing 226 of the weldment 224 includes holes or slots to allow the cable 223 to exit the flight chamber 201 to be attached to the mounting plate 225. At the base of the flight chamber 201, the fairing 226 overlaps the air chamber wall of the fourth corner 209 (the contraction corner) to form a continuous surface between the two. The panel 228 is securely mounted to the cover plate 227 around the fairing 226 to define the wall of the flight chamber 201. For example, the panel 228 can be positioned on a placement block so that the inner surface of the panel 228 is aligned with the inner surface of the fairing 226, the retaining angle can be fixed to the top surface of the cover plate 227 on the opposite side of the panel 228, and the structural adhesive can be applied in the channel between the retaining angle and the fairing 226 to fix the panel 228 in place. Depending on the desired cross-sectional geometry of the flight chamber 201 used for a particular design, the panel 228 can be curved, flat, or a mixture of the two. Panel 228 is typically made of a transparent material to allow activities occurring within flight chamber 201 to be observed from other areas of the wind tunnel facility.

[0086] It should be appreciated that the cable layer assembly 222 can be accessed from below (rather than above) the weldment 224 for maintenance. In this manner, there is no need to access the cover plate 227, or even to seal the cover plate 227 relative to the commercial area surrounding the flight chamber 201. Instead, a finished floor (e.g., carpet, wood, tile, composite, etc.) can be installed above the cover plate 227 to provide customers with a streamlined or minimalist abstract aesthetic of the floor surrounding the flight chamber 201. For maintenance purposes, such as to inspect or replace components of the cable layer assembly, the frame structure 220 may include a walkway to facilitate access to the cables 223 and mounting plate 225 from below the weldment 224 (see FIG. 2 ). Fig.16 ). In addition, the subfloor or basement area around the fourth corner 209 is typically ventilated to the airflow plenum through openings in the flyer assembly area adjacent to the flight chamber entrance to equalize the pressure between the two, which means that the cable layer design does not negatively affect the environmental conditions of this generally non-public area. In addition, the base plate does not need to cover the bottom of the weldment or structurally mount the weldment to a separate load-bearing beam or other support element of the wind tunnel facility structure, which further reduces construction / manufacturing costs and simplifies the assembly process.

[0087] In some embodiments of a double-return recirculation wind tunnel, the height between the cable 223 and the bottom surface of the wind tunnel air chamber below the cable (or the base of the corner) is less than or equal to 1.3 times the diameter of the flight chamber. In other words: [vertical distance between the cable and the base of the corner] ≤ [1.3×the diameter of the flight chamber]. In some embodiments of a single-loop recirculation wind tunnel, the height between the cable 223 and the bottom surface of the wind tunnel air chamber below the cable (or the base of the corner) is less than or equal to 1.9 times the diameter of the flight chamber. In other words: [vertical distance between the cable and the base of the corner] ≤ [1.9×the diameter of the flight chamber].

[0088] Go to Fig.25 (depicting a single return flow path) and Fig.26 (depicting dual return flow paths), a recirculation wind tunnel 300 according to the present disclosure may further include a stepped turn 301 located in one or more corners 302 of the wind tunnel 300. Although the stepped turn 301 is depicted as being located in a first corner, it should be appreciated that the stepped turn 301 may be located in other corners 302 of the wind tunnel as desired. The stepped turn 301 splits the flow path of the plenum 303 into two or more flow paths. In the depicted embodiment, the corner exit flow path corresponds to a duct 304 that houses a fan 305 that generates airflow through the wind tunnel 300. It should be further appreciated that the duct 304 does not necessarily need to house the fan 305. A guide vane structure 306 may be disposed within the corner 302, at the entrance of each duct 304, to redirect the airflow between the plenum 303 and the duct 304. With this configuration, the stepped turn 301 bifurcates the airflow to provide a space or gap 307 between adjacent ducts 304. For example, the stepped turn 301 can be used to establish sufficient spacing between multiple independent duct fans 305, which can reduce the wind tunnel flow path length required along the longitudinal axis through the duct 304 because the fans 305 can be arranged closer to the corner 302 through the stepped turn 301. In other embodiments, the stepped turn 301 can establish spacing to accommodate and clear elements (such as structural beams / columns, vents, wires, etc.) arranged in the space 307. Therefore, the size of the wind tunnel 300 can be reduced, which can enable the wind tunnel to be built in a location with limited space. Similarly, the establishment of the space or gap 307 can provide additional freedom and options in the design of the facility. In addition, the advantages of the stepped turn 301 are not necessarily limited to vertical wind tunnels; within the spirit and scope of the present disclosure, horizontal wind tunnels can also use the stepped turn structure to achieve this benefit.

[0089] Reference now Fig.29 and Fig.30, shows yet another embodiment of a recirculation wind tunnel 400 according to the present disclosure. As depicted, the wind tunnel 400 can be designed in the same manner as the above-described embodiments, meaning that the above description applies equally to this embodiment, except that the second corner and the vertical return plenum of the wind tunnel 400 are divided into more than one flow path. The wind tunnel 400 includes a first return air tower 402 and a second return air tower 404. The return air towers 402, 404 correspond to the second corner and the vertical return plenum. The return air towers 402, 404 provide separate parallel flow paths for the airflow. Therefore, in this embodiment, the airflow is divided between each side or loop of the wind tunnel 400 at the first corner, and further divided between two flow paths passing through the upper horizontal plenum, the second corner, and the vertical return plenum. The flow paths of the return air towers 402, 404 can then rejoin at the third corner. In the depicted embodiment, the return air towers 402, 404 are physically separated by a gap (see Fig.30 ), but other embodiments may have a physically separate structure shared by two return air towers without a gap between the two return air towers (e.g., a plenum dividing wall that defines a portion of the flow path of the two return air towers). This separation between the return air towers 402, 404 allows the vertical return plenum to expand more quickly (increase in cross-sectional area) between the second and third corners, but does not establish airflow separation from the plenum wall, which can lead to increased turbulence, instability, and efficiency losses. If the cross-sectional area of ​​the second and third corners remains constant, the length of the vertical return plenum can therefore be reduced using separate return air towers 402, 404 compared to a single flow path vertical return plenum, but there is no separation of the airflow from the wall due to the increased wall bifurcation capacity over the same distance. The reduction in length or height of the vertical return plenum can reduce the overall height of the wind tunnel 400, and accordingly reduce the height of the facility that houses the wind tunnel 400. The benefits of height reduction discussed above for the converging corners also apply here. It should be appreciated that the return air towers 402 , 404 described as separate may be integrated into the wind tunnel 200 described previously.

[0090] Reference now Fig.31 and Fig.32 The recirculating vertical wind tunnel according to the present disclosure may further include a flyer exchange device 500 . Fig.31A partial floor plan of a schematic wind tunnel facility surrounding a flight chamber area is shown. The wind tunnel includes a flight chamber 502 having a circular or substantially circular cross section in which participants perform indoor skydiving, but other embodiments may include cross sections of different shapes. A control room 504 is arranged adjacent to the flight chamber 502, in which facility personnel can monitor the activities of flyers (e.g., if a participant is injured) and wind tunnel conditions (e.g., temperature, wind speed, etc.) and control the wind tunnel system as needed. An enclosed corridor 506 connects the flight chamber 502 to the flyer exchange device 500. For example, a participant can step through an open door frame formed in the wall of the flight chamber 502 to move between the corridor 506 and the flight chamber 502. The corridor 506 is sealed relative to a surrounding observation area 508 of the facility. The flyer exchange device 500 includes an enclosed cabin with two opposing doors. One of the doors is an outer door 510, which is connected to the observation area 508. The other door is an inner door 512, which is connected to the corridor 506. When a participant wishes to enter the wind tunnel, the outer door 510 of the flyer exchange 500 is first opened. The participant then enters the flyer exchange 500 from the observation area 508 through the outer door 510. The outer door 510 is then closed. Once the participant is inside the flyer exchange 500 and the outer door 510 is closed, the inner door 512 may then be opened. The participant then steps through the inner door 512 to exit the flyer exchange 500 and enter the corridor 506. At this point, the participant may continue through the corridor 506 to enter the flight chamber 502. The inner door 512 may then be closed. The participant may exit the wind tunnel in the reverse process.

[0091] The operation of doors 510, 512 can be automatic, manual or both. For example, opening and / or closing can be operated by a button or another input device from operator control room 504. Similarly, buttons or other input devices can be arranged on doors 510, 512 themselves, to be operated by a participant, for example, located in flyer exchange device 500 and / or corridor 506. Automatic timing operation can also be used to control when doors 510, 512 are opened and / or closed, and the order of controlling specific door opening and / or closing. Sensors can also be used to perform automatic door operation. In addition, RFID or barcode / QR code readers can be arranged near outer door 510 to scan wristbands or pass worn by participants, thereby confirming authorized entry before outer door 510 is opened.

[0092] Therefore, it should be appreciated that the flyer exchange device 500 provides a controlled and continuous mechanism to exchange flyers between the flight cabin 502 and the observation area 508. Pressure and noise exchange between the flight cabin 502 and the observation area 508 is prevented or reduced by a double door system. The entry and exit of users can be controlled or tracked by an identification scanning method. In addition, the existing wind tunnel facility has an entire assembly cabin area for accommodating multiple groups of participants and extending around the periphery of the flight cabin, which is less obstructed from the observation area 508 to the flight cabin 502 than the existing wind tunnel facility. This aspect also frees up additional layer space of the observation area 508 adjacent to the flight cabin 502 for other users.

[0093] Figure 33 to Figure 35 An embodiment of a recirculating vertical wind tunnel with a flyer exchange device 500 according to the present disclosure is shown. A commercial level of the facility (not shown) is generally located at the same level as the base of the flight chamber 502, the corridor 506, and the flyer exchange device 500. The commercial level separates the space above the commercial level (e.g., the observation area 508 surrounding the flight chamber 502) from the space below the commercial level (e.g., the area around the pinch corners, the lower horizontal air chamber, etc.). Fig.34 and Fig.35 As seen in the figure, the corridor 506 may be aerodynamically connected to at least one air vent 514. For example, the floor of the corridor 506 may include one or more openings that link the interior of the corridor 506 to the interior of the air vent 514. The air vent 514 may be aerodynamically connected to the external environment of the building, or aerodynamically connected to the space below the commercial layer (e.g., the area around the contraction corner, the lower horizontal air chamber, etc.). In the depicted embodiment, the air vent 514 is a closed duct that extends to connect to the outside of the building, rather than opening to the space below the commercial layer, which may cause suction in the space. The airflow between the corridor 506 and the air vent 514 is represented by an arrowed line in the figure. Therefore, the pressure in the corridor 506 is balanced by aerodynamically connecting to the air vent 514. This reduces noise (e.g., the dull sound of pressure waves) and improves the comfort of users in the corridor 506. In the present embodiment with the ventilation corridor 506, the double doors 510, 512 of the flyer exchange device 500 function more to control the ingress and egress of users and reduce noise exchange between the corridor 506 and the commercial or observation area 508, rather than to prevent pressure exchange.

[0094] Although many aspects and embodiments have been discussed, those skilled in the art will recognize certain modifications, permutations, additions, and sub-combinations thereof. It is therefore intended that the appended claims be interpreted as including all such modifications, permutations, additions, and sub-combinations within the true spirit and scope of the claims. Each embodiment described herein has numerous equivalents.

[0095] The terms and expressions that have been used are used as descriptive terms, rather than limiting terms, and when such terms and expressions are used, it is not intended to exclude any equivalents of the features shown and described or parts thereof; it is recognized that various modifications can be made within the scope of the claimed invention. Therefore, it should be understood that although the present invention is specifically disclosed through certain embodiments and optional features, modifications and variations of the concepts disclosed herein may be adopted by those skilled in the art, and such modifications and variations are considered to be within the scope of the invention as defined by the appended claims. Whenever a range is given in the specification, all intermediate ranges and subranges, as well as all independent values, included within the given range are intended to be included in the present disclosure. When a Markush group or other grouping is used herein, all independent members of the group and all possible combinations and subcombinations of the group are intended to be included in the present disclosure individually.

[0096] Generally, the terms and phrases used herein have their generally accepted meanings, which can be found by reference to standard texts, publications, journal literature and contexts known to those skilled in the art. The above definitions are provided to clarify their specific use in the context of the present invention.

[0097] In Example 1, a vertical wind tunnel for indoor skydiving is provided, the vertical wind tunnel comprising:

[0098] Recirculating air flow plenum;

[0099] a flight chamber housed within the first vertical member of the airflow plenum;

[0100] The recirculating airflow plenum includes a top horizontal member, a bottom horizontal member, and a second vertical member;

[0101] A corner section is arranged below the flight cabin and connects the bottom horizontal air chamber to the flight cabin, the corner section comprising a guide blade structure having a centerline and a circular arch;

[0102] wherein the bottom horizontal air chamber has a first section and a second section, the first section and the second section extending from the second vertical member to the first vertical member, the first section being connected to the second vertical member, and the second section being connected to the corner section;

[0103] The first section has a substantially rectangular cross-section;

[0104] The second section contracts the airflow between the first section and the corner section, the second section having an upper surface;

[0105] The wall of the second section includes a transition section between the first section and the corner section;

[0106] The corner section causes airflow to contract between the second section and the flight cabin;

[0107] The wall of the corner section includes a transition section between the second section and the flight compartment, thereby reducing the height of the recirculation airflow plenum;

[0108] The upper surface of the second section has a dome shape which substantially corresponds to the dome of the corner section, which extends from the center line at least partially in the direction of the first section.

[0109] In Example 2, the vertical wind tunnel of Example 1 further includes another bottom horizontal air chamber, a corner section connects the flight cabin to each bottom horizontal air chamber, and the guide vane structure has two circular arches.

[0110] In Example 3, based on the vertical wind tunnel of Example 1, the first section includes one or more corner transition portions that transition between a hard corner near the second vertical member to a rounded corner at the second section of the bottom horizontal air chamber.

[0111] In Example 4, based on the vertical wind tunnel of Example 3, the one or more corner transition portions extend along at least a majority of the length of the first section.

[0112] In Example 5, based on the vertical wind tunnel of Example 3, the one or more corner transition portions are formed by a wall of the first section.

[0113] In Example 6, based on the vertical wind tunnel of Example 3, the one or more corner transition portions are formed by a separate structure installed in the first section.

[0114] In Example 7, based on the vertical wind tunnel of Example 1, the floor of the bottom horizontal air chamber includes a bowl shape configured to drain liquid accumulated in the vertical wind tunnel.

[0115] In Example 8, in the vertical wind tunnel based on Example 7, the lowest point of the floor of the bottom horizontal air chamber is arranged at a point between the first section and the second section.

[0116] In Example 9, based on the vertical wind tunnel of Example 7, the bowl shape of the floor of the bottom horizontal air chamber is extended to the base of the second vertical member.

[0117] In Example 10, in the vertical wind tunnel based on Example 1, the base of the second vertical member is arranged higher than the base of the corner section along the vertical direction.

[0118] In Example 11, based on the vertical wind tunnel of Example 1, the base of the second vertical member has a widened rectangular geometry to reduce the excavation depth.

[0119] In Example 12, based on the vertical wind tunnel of Example 1, the flight chamber comprises a circular or substantially circular cross-section at the junction with the corner section.

[0120] In Example 13, in a vertical wind tunnel based on Example 1, the walls of the corner sections form an inlet constriction which is oriented vertically around the central axis of the flight chamber between the guide vane structure and the flight chamber.

[0121] In Example 14, in a vertical wind tunnel based on Example 13, an inlet constriction is mounted directly to one or more domes of a guide vane structure.

[0122] In Example 15, in the vertical wind tunnel based on Example 1, the bottom horizontal air chamber is directly connected to the dome of the one or more domes of the guide vane structure.

[0123] In Example 16, based on the vertical wind tunnel of Example 1, one or more round arches of the guide frame structure at least partially define a recirculation airflow plenum passing through the corner section.

[0124] In Example 17, in a vertical wind tunnel based on Example 1, the wall of the corner section at least partially forms an S-shaped double curvature profile between the flight chamber and one or more rounded arches of the guide blade structure.

[0125] In Example 18, in a vertical wind tunnel based on Example 1, a corner section connects the flight cabin to two bottom horizontal air chambers, and the cross-sectional area of ​​the corner section decreases in a ratio of about 2:1 between the two bottom horizontal air chambers and the flight cabin.

[0126] In Example 19, in a vertical wind tunnel based on Example 1, a corner section connects the flight cabin to two bottom horizontal plenums, and the recirculation airflow plenum through the corner section has a semi-elliptical cross-section at each of the two bottom horizontal plenums, and a circular or substantially circular cross-section at the flight cabin.

[0127] In Example 20, based on the vertical wind tunnel of Example 1, one or more domes span between the ends of the centerline and slope upward.

[0128] In Example 21, in the vertical wind tunnel based on Example 20, each of the one or more circular arches of the guide frame structure is inclined upward at approximately 45 degrees relative to a horizontal plane.

[0129] In Example 22, based on the vertical wind tunnel of Example 1, the one or more domes of the guide blade structure include a first dome and a second dome, and the first dome extends in a direction opposite to the second dome.

[0130] In Example 23, in a vertical wind tunnel based on Example 1, the guide vane structure includes a guide vane extending across each of one or more arches of the guide frame structure, the guide vane being configured to redirect airflow from a bottom horizontal plenum upward to a flight chamber.

[0131] In Example 24, based on the vertical wind tunnel of Example 1, the guide vane structure provides structural support for one or more air chamber structures of the vertical wind tunnel.

[0132] In Example 25, in a vertical wind tunnel based on Example 1, the centerline of the guide vane structure extends perpendicular or substantially perpendicular to the airflow through the bottom horizontal plenum.

[0133] In Example 26, in a vertical wind tunnel based on Example 1, the centerline of the guide vane structure is aligned with a horizontal centerline passing through the flight chamber.

[0134] In Example 27, in a vertical wind tunnel based on Example 1, a centerline of the guide vane structure includes a ridge having a curved surface that transitions from horizontal or substantially horizontal to vertical or substantially vertical.

[0135] In Example 28, in a vertical wind tunnel based on Example 1, the guide vane structure includes a frame structure disposed outside the recirculation air flow plenum, and one or more round arches of the guide vane structure are attached to the frame structure.

[0136] In Example 29, in a vertical wind tunnel based on Example 28, a cable layer assembly is mounted to a frame structure of a guide blade structure, the cable layer assembly including a plurality of cables extending across a flight chamber.

[0137] In Example 30, the vertical wind tunnel of Example 1 is a double-loop recirculation wind tunnel, spanning a height between the cable layer of the flight chamber and the base of the corner section of ≤ (diameter of the flight chamber×1.3).

[0138] In Example 31, the vertical wind tunnel of Example 1 is a single-loop recirculating wind tunnel, spanning a height between the cable layer of the flight chamber and the base of the corner section of ≤ (diameter of the flight chamber×1.9).

[0139] In Example 32, in a vertical wind tunnel based on Example 1, a wall of a second section of a bottom horizontal air chamber forms an inlet constriction, which is oriented horizontally between a first section and a corner section of the bottom horizontal air chamber.

[0140] In Example 33, in the vertical wind tunnel based on Example 1, the recirculation airflow plenum through the second section of the bottom horizontal plenum includes a substantially rectangular cross-section near the first section and a semi-elliptical or substantially semi-elliptical cross-section near the corner section.

[0141] In Example 34, a guide vane structure for a corner of a vertical wind tunnel is provided, wherein the vertical wind tunnel forms a recirculation airflow chamber, and the guide vane structure comprises:

[0142] a frame structure disposed at least partially outside the recirculation air flow chamber;

[0143] The frame structure consists of two round arches;

[0144] The arch spans between the ends of the center line;

[0145] Each round arch is inclined at an angle relative to the horizontal plane;

[0146] The arches extend in opposite directions from each other; and

[0147] A guide vane is mounted along each of the two circular arches, the guide vane being disposed within the recirculation air flow plenum and configured to redirect the air flow passing through the corner.

[0148] In Example 35, based on the guide vane structure of Example 34, the corner of the vertical wind tunnel is arranged below the flight cabin, and the guide vanes redirect the airflow from the horizontal air chamber of the vertical wind tunnel upward to the flight cabin.

[0149] In Example 36, based on the guide vane structure of Example 34, the apex of each circular arch is connected to a beam extending between the columns of the frame structure.

[0150] In Example 37, based on the guide vane structure of Example 34, the frame structure includes two cross beams and four columns arranged outside the recirculation air flow plenum, and each cross beam extends between two columns of the frame structure.

[0151] In Example 38, based on the guide vane structure of Example 37, each beam extends over a portion of the recirculation airflow plenum.

[0152] In Example 39, based on the guide vane structure of Example 34, the rounded arch forms at least a part of the recirculation air flow plenum.

[0153] In Example 40, a guide vane structure based on Example 34 structurally supports an air chamber structure of a vertical wind tunnel.

[0154] In Example 41, based on the guide vane structure of Example 34, the air chamber wall of the vertical wind tunnel is directly connected to the dome of the guide vane structure.

[0155] In Example 42, based on the guide blade structure of Example 34, the circular arch is inclined at about 45 degrees relative to the horizontal plane.

[0156] In Example 43, based on the guide vane structure of Example 34, the guide vane includes one or more channels to allow a cooling fluid to flow through the guide vane.

[0157] In Example 44, based on the guide blade structure of Example 34, the cable layer assembly is mounted to the frame structure.

[0158] In Example 45, based on the guide vane structure of Example 34, the center line is set by a ridge.

[0159] In Example 46, based on the guide vane structure of Example 45, the ridge includes two opposing curved surfaces that transition between horizontal or substantially horizontal to vertical or substantially vertical.

[0160] In Example 47, the guide blade structure of any one of Examples 34-46 is included in the cable layer assembly of any one of Examples 48-69 described below and / or the vertical wind tunnel of any one of Examples 1-33 described above.

[0161] In Example 48, a cable layer assembly for a vertical wind tunnel is provided, wherein the vertical wind tunnel forms a recirculating airflow plenum including a flight chamber, the cable layer assembly comprising:

[0162] a frame structure supporting weldments arranged around the base of the flight chamber;

[0163] Each weldment has at least an air chamber wall fairing and a cable mounting plate;

[0164] The plenum wall fairing forms a surface that is flush or substantially flush with an adjacent plenum wall of the recirculation airflow plenum;

[0165] The air chamber wall fairing includes a slot to accommodate a plurality of cables extending therethrough;

[0166] The cables span the recirculating airflow plenum to form a cable layer at the base of the flight chamber;

[0167] The ends of each cable are secured to the mounting plates of the opposing weldments;

[0168] Wherein, each cable has the same or substantially the same length.

[0169] In Example 49, based on the cable layer assembly of Example 48, the frame structure includes a support column arranged outside the recirculation air flow plenum of the wind tunnel, and the weldment is mounted to the support column.

[0170] In Example 50, based on the cable layer assembly of Example 48, the weld can be accessed from below during cable maintenance.

[0171] In Example 51, based on the cable layer assembly of Example 48, the frame structure supports one or more user platforms located outside the recirculating airflow plenum of the wind tunnel, the user platforms being arranged below the one or more weldments for easy access during cable maintenance.

[0172] In Example 52, based on the cable layer assembly of Example 51, the cover plate forms a floor surface adjacent to the flight cabin.

[0173] In Example 53, the cable layer assembly of Example 48 further includes:

[0174] a plurality of eyebolts extending through the openings in the cable mounting plate, an end of each cable being attached to an eyebolt of an opposing weldment;

[0175] a plurality of compression springs disposed along the cable mounting plate opposite the flight compartment, each compression spring being configured to bias the eyebolt away from the flight compartment;

[0176] Thereby, the cable is pulled tensioned across the flight chamber by the tension introduced into the cable from the compression spring via the eyebolt; and

[0177] When sufficient opposing force is applied to the cable, the compression spring is compressed, which allows the eyebolt to move toward the flight chamber, thereby providing a greater bend in the cable.

[0178] In Example 54, based on the cable layer assembly of Example 53, a sleeve is disposed in the opening of the cable mounting plate so that the eye bolt is installed through the sleeve.

[0179] In Example 55, based on the cable layer assembly of Example 53, a nut and a washer are provided on the end of each eye bolt opposite to the cable, a compression spring is arranged between the cable mounting plate and the nut and the washer, and the compression spring is operably connected to the eye bolt through the nut and the washer.

[0180] In Example 56, the cable layer assembly of Example 48 has four welds.

[0181] In Example 57, the cable layer assembly of Example 48 has four weldments, and the cable mounting plates of the weldments form or substantially form a square.

[0182] In Example 58, based on the cable layer assembly of Example 48, the cable mounting plate of one weldment is parallel or substantially parallel to the cable mounting plate of the weldment opposite with respect to the flight compartment.

[0183] In Example 59, based on the cable layer assembly of Example 48, the cable mounting plate of one weldment is perpendicular or substantially perpendicular to the cable mounting plate of an adjacent weldment.

[0184] In Example 60, based on the cable layer assembly of Example 48, the cable layer formed between the welds is square or substantially square.

[0185] In Example 61, based on the cable layer assembly of Example 48, the cables intersect other cables perpendicularly when extending across the flight compartment.

[0186] In Example 62, based on the cable layer assembly of Example 48, the cables extend across the flight compartment in two directions, the two directions being perpendicular to each other.

[0187] In Example 63, based on the cable layer assembly of Example 48, the cables extending between the two opposing welds are parallel or substantially parallel to each other.

[0188] In Example 64, based on the cable layer assembly of Example 48, the cross-section of the flight chamber is circular or substantially circular.

[0189] In Example 65, based on the cable layer assembly of Example 48, the intersecting cables forming the cable layer are braided with each other.

[0190] In Example 66, based on the cable layer assembly of Example 48, each weldment further has a cover plate extending across the air chamber wall fairing and the cable mounting plate, the cover plate being configured not to be removed during cable maintenance.

[0191] In Example 67, based on the cable layer assembly of Example 48, the cover plate is provided with a retaining angle for mounting a wall panel of the flight cabin, and the wall panel is arranged above the cover plate and located between the retaining angle and the air chamber wall fairing of the weldment.

[0192] In Example 68, based on the cable layer assembly of Example 48, adjacent air chamber walls are shaped to accommodate air chamber wall fairings extending at least partially above the adjacent air chamber walls, and the adjacent air chamber walls are shaped to accommodate the air chamber wall fairings to form a flush or substantially flush surface.

[0193] In Example 69, in a cable layer assembly based on any one of Examples 48-68, the cable layer assembly is included in the guide blade structure of any one of Examples 34-47 described above and / or the vertical wind tunnel of any one of Examples 1-33 described above.

[0194] In Example 70, a wind tunnel is provided, the wind tunnel comprising:

[0195] an air chamber connected to at least one second air chamber via a corner section, the corner section redirecting airflow through the wind tunnel from the first air chamber to the second air chamber;

[0196] The corner section has at least one outlet side connected to the two or more ducts of the second air chamber, and the guide vane structure is arranged along the outlet side of the corner section to redirect the air flow from the first air chamber directly into the plurality of ducts of the second air chamber;

[0197] Wherein, the exit side of the corner section includes a stepped turning portion;

[0198] The stepped turn allows the airflow to be divided into a plurality of ducts entering the second air chamber; and

[0199] Along the direction of air flow through the first air chamber, the pipes of the second air chamber are separated from each other;

[0200] Thereby, between adjacent ducts of the second air chamber, a gap space is formed adjacent to the outlet side of the corner section.

[0201] In Example 71, the wind tunnel of Example 70 has two second air chambers.

[0202] In Example 72, based on the wind tunnel of Example 71, each of the two second air chambers has two or more ducts, and the two or more ducts are connected to the corner section through a stepped turn.

[0203] In Example 73, based on the wind tunnel of Example 70, the second air chamber has only two ducts.

[0204] In Example 74, in a wind tunnel based on Example 70, the outlet side of the corner section is connected to the duct of the second air chamber at an angle of about 45 degrees relative to the direction of air flow through the first air chamber.

[0205] In Example 75, in a wind tunnel based on Example 70, the guide vane structure is arranged at an angle of about 45 degrees relative to the direction of airflow through the first air chamber.

[0206] In Example 76, in a wind tunnel based on Example 70, a duct of the second chamber that is farthest from the first chamber when connected to the outlet side of the corner section extends closer to the longitudinal axis of the first chamber than an adjacent duct of the second chamber that extends to the longitudinal axis of the first chamber.

[0207] In Example 77, based on the wind tunnel of Example 70, the cross-section of each duct of the second air chamber has the same or substantially the same size.

[0208] In Example 78, based on the wind tunnel of Example 70, each duct of the second air chamber accommodates a fan for generating airflow.

[0209] In Example 79, based on the wind tunnel of Example 70, the interstitial space formed by the stepped turns between adjacent ducts accommodates one or more structural elements of a wind tunnel facility for the wind tunnel.

[0210] In Example 80, in the wind tunnel according to any one of Examples 70-79, the wind tunnel is a vertical wind tunnel for indoor skydiving.

[0211] In Example 81, based on the wind tunnel of Example 80, the vertical wind tunnel is the vertical wind tunnel of any one of Examples 1-33 described above.

[0212] List of reference numerals

[0213] 100 Wind Tunnel 300 Wind Tunnel

[0214] 101 Flight Chamber 301 Step Turning Section

[0215] 102 Diffuser 302 Corner

[0216] 103 First Corner 303 Air Chamber

[0217] 104 Upper horizontal air chamber 304 pipeline

[0218] 105 Second corner 305 Fan

[0219] 106 Vertical return air chamber 306 Guide blade structure

[0220] 107 Third corner 307 Space or gap

[0221] 108 Lower horizontal air chamber 400 Recirculation wind tunnel

[0222] 109 Fourth Corner 402 First Return Air Tower

[0223] 110 Inlet shrinkage 404 Second return air tower

[0224] 111 First section of lower horizontal air chamber 500 Flyer exchange device

[0225] 112 The second section of the lower horizontal air chamber 502 Flight chamber

[0226] 113 Guide vanes 504 Control room

[0227] 200 Wind Tunnel 506 Corridor

[0228] 201 Flight Chamber 508 Observation Area

[0229] 202 Diffuser 510 External Door

[0230] 203 First Corner 512 Inner Door

[0231] 204 upper horizontal air chamber 514 ventilation hole

[0232] 205 Second Corner

[0233] 206 Vertical return chamber

[0234] 207 The Third Corner

[0235] 208 Lower horizontal air chamber

[0236] 209 Fourth corner (contraction corner)

[0237] 210 Fan

[0238] 211 The first section of the lower horizontal air chamber

[0239] 212 The second section of the lower horizontal air chamber

[0240] 213 Corner transition

[0241] 214 Arch with a narrow corner

[0242] 215 Centerline

[0243] 216 Bottom surface (floor)

[0244] 217 Lowest point of the floor

[0245] 218 Contraction of the second section

[0246] 219 Transition to the second section

[0247] 220 frame structure

[0248] 221 Guide vane

[0249] 222 Cable Layer Components

[0250] 223 Cable

[0251] 224 Welding parts

[0252] 225 Mounting plate

[0253] 226 Fairing

[0254] 227 Cover

[0255] 228 Flight Chamber Wall Panel

[0256] 229 Eyebolt

[0257] 230 Compression spring

[0258] 231 Nut

[0259] 232 Washer

[0260] 233 Casing

Claims

1. A vertical wind tunnel for indoor skydiving, characterized in that: The vertical wind tunnel comprises: Recirculating air flow plenum; a flight chamber housed within the first vertical member of the airflow plenum; The recirculating airflow plenum includes a top horizontal member, a bottom horizontal plenum, and a second vertical member; A corner section is arranged below the flight cabin and connects the bottom horizontal air chamber to the flight cabin, the corner section including a guide blade structure having a centerline and a round arch; wherein the bottom horizontal air chamber has a first section and a second section, the first section and the second section extending from the second vertical member to the first vertical member, the first section connected to the second vertical member, and the second section connected to the corner section; The first section has a substantially rectangular cross-section; The second section causes airflow to converge between the first section and the corner section, the second section having an upper surface; The wall of the second section includes a transition section between the first section and the corner section; The corner section causes airflow to contract between the second section and the flight chamber; The wall of the corner section includes a transition section between the second section and the flight chamber, thereby reducing the height of the recirculation airflow plenum; The upper surface of the second section has a rounded shape substantially corresponding to the rounded shape of the corner section, which extends from the center line at least partially in the direction of the first section.

2. The vertical wind tunnel for indoor skydiving according to claim 1, further comprising another bottom horizontal air chamber, the corner section connecting the flight cabin to each bottom horizontal air chamber, the guide vane structure having two circular arches.

3. The vertical wind tunnel for indoor skydiving according to claim 1, wherein: The first section includes one or more corner transitions that transition between a hard corner near the second vertical member to a rounded corner at the second section of the bottom horizontal plenum.

4. The vertical wind tunnel for indoor skydiving according to claim 3, wherein: The one or more corner transition portions extend along at least a majority of the length of the first segment.

5. The vertical wind tunnel for indoor skydiving according to claim 3, wherein: The one or more corner transition portions are formed by a wall of the first section.

6. The vertical wind tunnel for indoor skydiving according to claim 3, wherein: The one or more corner transition portions are formed by a separate structure mounted within the first section.

7. The vertical wind tunnel for indoor skydiving according to claim 1, wherein: In the vertical direction, a base of the second vertical member is arranged higher than a base of the corner section.

8. The vertical wind tunnel for indoor skydiving according to claim 1, wherein: The base of the second vertical member has a widened rectangular geometry to reduce digging depth.

9. The vertical wind tunnel for indoor skydiving according to claim 1, wherein: The wall of the corner section forms an inlet contraction which is oriented vertically around a central axis of the flight chamber between the guide vane structure and the flight chamber.

10. The vertical wind tunnel for indoor skydiving according to claim 9, wherein: The inlet constriction is mounted directly to one or more domes of the guide vane structure.

11. The vertical wind tunnel for indoor skydiving according to claim 1, wherein: The bottom horizontal air chamber is directly connected to a dome of the one or more domes of the guide vane structure.

12. The vertical wind tunnel for indoor skydiving according to claim 1, wherein: One or more circular arches of the guide vane structure at least partially define the recirculation airflow plenum through the corner section.

13. The vertical wind tunnel for indoor skydiving according to claim 1, wherein: The wall of the corner section at least partially forms an S-shaped double curvature profile between the flight chamber and the one or more circular arches of the guide blade structure.

14. The vertical wind tunnel for indoor skydiving according to claim 1, wherein: The corner section connects the flight compartment to two bottom horizontal plenums, the recirculation air flow plenum passing through the corner section having a semi-elliptical cross section at each of the two bottom horizontal plenums and a circular or substantially circular cross section at the flight compartment.

15. The vertical wind tunnel for indoor skydiving according to claim 1, wherein: One or more domes span between the ends of the centerline and slope upwardly.

16. The vertical wind tunnel for indoor skydiving according to claim 1, wherein: The guide vane structure provides structural support for one or more air chamber structures of the vertical wind tunnel.

17. The vertical wind tunnel for indoor skydiving according to claim 1, wherein: The centerline of the guide vane structure includes a ridge having a curved surface that transitions from horizontal or substantially horizontal to vertical or substantially vertical.

18. The vertical wind tunnel for indoor skydiving according to claim 1, wherein: The wall of the second section of the bottom horizontal air chamber forms an inlet constriction that is oriented horizontally between the first section of the bottom horizontal air chamber and the corner section.

19. The vertical wind tunnel for indoor skydiving according to claim 1, wherein: The recirculation air flow plenum through the second section of the bottom horizontal plenum includes a substantially rectangular cross-section proximate the first section and a semi-elliptical or substantially semi-elliptical cross-section proximate the corner section.

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