A maglev train track beam and bridge for wind tunnel testing

Abstract

This invention provides a maglev train track beam column for wind tunnel experiments. The cross-section of the beam column is symmetrical along its axis, and the cross-section is a flat teardrop shape, bulging outward from the middle and contracting inward at both ends. The middle and both ends are connected by smooth arcs to form a streamlined structure. The two ends of the beam column's cross-section are a first end and a second end, both of which are arc-shaped, with the radius of the arc at the first end being larger than that at the second end. This invention also provides a bridge for wind tunnel experiments, including a track beam body and the aforementioned beam column, with the track beam body mounted on the beam column. This invention can reduce the influence of vortices on the sides and tail of the high-speed train track beam column during experiments, reduce aerodynamic noise generated by the beam column's wake vortex, and thus improve experimental accuracy.

Description

Technical Field

[0001] This invention belongs to the field of wind tunnel testing technology, and particularly relates to a maglev train track beam and bridge for wind tunnel testing. Background Technology

[0002] To minimize land acquisition, current high-speed railways typically use bridges instead of roads. Since high-speed trains spend the vast majority of their time running on bridges, the aerodynamic characteristics of high-speed trains on bridges are a hot topic in train aerodynamics research. Wind tunnel experiments are an important research method.

[0003] Currently, there are three methods for simulating bridge beams and columns in wind tunnel experiments. Method one is the single cylindrical scheme, such as... Figure 1 As shown, the first method is a scaled-down version of the actual cylindrical beam, installed at the transverse center of the bridge beam perpendicular to the train's direction of travel; the second method is a double-cylinder scheme, as shown... Figure 2 As shown, the actual double cylindrical beams are scaled down from the train model and installed side-by-side on both sides of the bridge beam perpendicular to the train's direction of travel; Scheme 3 has a cross-section with semicircles at both ends and a rectangle in the middle, as shown. Figure 3 As shown, it is also based on the actual double cylindrical beams and columns, scaled down according to the train model.

[0004] Of these three schemes, Scheme 1 is the most commonly used scheme in high-speed train bridge wind tunnel experiments. Its disadvantage is that unsteady vortices will detach in the cylindrical wake region, seriously affecting the measurement of high-speed train aerodynamic noise. Scheme 2 is also a commonly used scheme in high-speed train bridge wind tunnel experiments. In addition to the unsteady vortices detaching in the cylindrical wake region, which seriously affect the measurement of high-speed train aerodynamic noise, the vortices detaching from the outer side will affect the sidewalls of the bridge and the high-speed train, thus affecting the aerodynamic performance of the bridge and the train. This effect does not exist in the actual operation of high-speed trains, which will introduce a large error into the experiment. Scheme 3 has basically the same disadvantages as Scheme 2, but it is larger in size, and the impact of the vortices detaching from the outer side is also greater. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to overcome the shortcomings of the existing technology and provide a maglev train track beam and bridge for wind tunnel experiments that can significantly reduce the influence of vortices on the sides and tails of the beams and columns of high-speed trains in experiments, without affecting the flow field around the high-speed train. At the same time, by changing the cross-section of the beams and columns, the separation of airflow is significantly delayed, the size of the tail vortex is significantly reduced, and the aerodynamic noise generated by the tail vortex of the beams and columns is reduced, thereby reducing its influence on the aerodynamic noise of the high-speed train.

[0006] To solve the above-mentioned technical problems, the technical solution proposed by this invention is as follows:

[0007] A maglev train track beam-column design for wind tunnel experiments is disclosed. The beam-column's cross-section is symmetrical along its axis, exhibiting a flat, teardrop shape that bulges outwards from the center and tapers inwards at both ends. The center and ends are connected by smooth arcs, forming a streamlined structure. The two ends of the beam-column's cross-section are designated as a first end and a second end, both with rounded ends. The radius of the rounded end at the first end is larger than that at the second end. Specifically, the beam-column's cross-section adopts a shape similar to that of an aircraft wing. Due to its streamlined design at the leading edge (first end), airflow on both sides only experiences small-scale separation at the tail (second end). Therefore, the vortex scale generated at the tail is smaller than in existing technologies, and its influence area is also smaller, thus not affecting the aerodynamic characteristics of the bridge and the high-speed train. Simultaneously, the generated aerodynamic noise is also relatively low, reducing the measurement error of high-speed train aerodynamic noise and improving the measurement accuracy of the experiment.

[0008] Preferably, in the aforementioned maglev train track beam and column used for wind tunnel experiments, the axis of the beam and column coincides with the axis of the track beam body, and the first end is positioned facing the windward side. Specifically, the beam and column are installed in the middle of the bridge. Because the first end faces the windward side, the streamlined leading edge of its cross-section can effectively delay the separation of airflow on both sides, reduce the size of the wake vortex, thereby reducing measurement errors caused by aerodynamic noise and improving measurement accuracy.

[0009] Preferably, the maglev train track beams and columns used in wind tunnel experiments described above are arranged in multiple equally spaced columns, with the first ends of adjacent columns facing each other, or the second ends of adjacent columns facing each other. The same ends of adjacent columns are arranged to face each other, meaning that each group of adjacent columns either has its first end facing the first end or its second end facing the second end. This arrangement can reduce airflow separation and wake vortices on both sides of long bridges, further improving measurement accuracy.

[0010] As a general technical concept, this invention also provides a bridge for wind tunnel experiments, including a track beam body and the aforementioned beam-column. The track beam body is mounted on the beam-column, and the interior of the track beam body has a guide cavity extending along its length. The guide cavity connects the two ends of the track beam body and forms a channel for airflow. The windward end of the track beam body is a planar structure without protrusions. By designing the track beam as a hollow structure to form the guide cavity, airflow can flow through it, solving the problem in the prior art where the large cross-section of the track beam causes significant turbulence when airflow reaches the end section of the track beam, resulting in large disturbances to the train flow field and leading to large errors in experimental results. Simultaneously, by reducing disturbances, the distance between the train head and the leading edge of the track beam can be significantly reduced, thereby greatly reducing the boundary layer thickness and improving the measurement accuracy of the experiment. The planar windward end of the track beam body in this structure reduces the distance for setting protruding guide slopes, thus helping to reduce the boundary layer thickness and the vibration of the track beam body cantilever, improving the accuracy and precision of wind tunnel experimental results.

[0011] Preferably, in the aforementioned bridge used for wind tunnel experiments, the track beam body comprises a top plate, side plates, and a bottom plate. These three plates enclose a track beam body with the flow-guiding cavity. The ends of the top, side, and bottom plates are each provided with a streamlined flow-guiding structure along their thickness direction. This flow-guiding structure includes an outer flow-guiding surface and an inner flow-guiding surface. The inner flow-guiding surface guides airflow towards the flow-guiding cavity, while the outer flow-guiding surface guides airflow outwards from the cavity. By using the top, side, and bottom plates to enclose the track beam body with the flow-guiding cavity, the area of ​​the cavity is increased, reducing disturbances at the windward end. Specifically, the flow-guiding structure can be a wedge-shaped structure or a rounded corner structure. This structure ensures that the airflow does not separate on the internal and external surfaces of the track beam body. The airflow does not split internally, allowing it to flow directly through the interior without obstruction, thus preventing internal flow field interference with the external flow field. Furthermore, the airflow does not separate on the external surface, preventing interference with the area around the train.

[0012] Preferably, in the bridge used for wind tunnel experiments described above, the guiding structure is a rounded corner structure located at the ends of the top plate, side plate, and bottom plate, with the outer and inner guiding surfaces arranged symmetrically. Specifically, the guiding structure is formed by rounding the ends of the top plate, side plate, and bottom plate. The inner guiding surface is the surface of the rounded corner structure on the side closest to the guiding cavity, and the outer guiding surface is the surface of the rounded corner structure facing outwards. The outer and inner guiding surfaces transition smoothly and continuously, with their boundary point located at the midpoint of the rounded corner arc, thus forming a symmetrical layout. That is, the radius of the rounded corner structure is half the plate thickness. The rounded corner structure resembles the side of a semi-cylinder. This structure ensures the guiding effect of the cross-section at the front end of the track beam, better preventing airflow separation between the internal and external surfaces of the track beam body. This prevents the separated airflow from affecting the flow field inside the guiding cavity and outside the track beam body, further reducing airflow interference around the train and thus improving experimental accuracy.

[0013] In the aforementioned bridge used for wind tunnel experiments, preferably, the thickness of the top plate, side plates, and bottom plate is 5–10 mm. Thinner plate materials are more conducive to mitigating or eliminating flow separation at the front end of the track beam, ensuring smooth airflow through the track beam's guide cavity and outer surface.

[0014] Preferably, the bridge used for wind tunnel experiments described above includes a test area for parking a maglev train model. The distance from the starting point of the test area to the windward end face of the track beam body is M, where 40mm ≤ M ≤ 50mm. Since the thickness of the boundary layer on the track beam increases with length, a thicker boundary layer has a greater impact on the results and should be minimized or eliminated as much as possible. This is especially important for wind tunnel experiments on maglev trains, where the gaps between the track beam and the bottom and sides of the train are very small, quickly flooding these gaps and severely interfering with the bottom flow field, leading to significant errors in the measurement results. Therefore, properly controlling the distance M can effectively control the boundary layer thickness, thereby improving the accuracy of experimental measurements.

[0015] In the aforementioned bridge used for wind tunnel experiments, preferably, the distance between the ends of the beam columns and the track beam body is L. The front and rear of the track beam body are cantilevered supports. The longer the cantilever length, the more severe the shaking during the experiment. This shaking will generate vertical velocity in the airflow above the bridge deck, causing changes in the flow field under the train and introducing significant measurement errors. Reasonably controlling the value of L can effectively reduce shaking, thereby reducing experimental measurement errors and improving measurement accuracy.

[0016] Compared with the prior art, the advantages of the present invention are as follows:

[0017] The maglev train track beam and column of the present invention, through its special shape and structural design, can significantly reduce the influence of vortices on the sides and tail of the high-speed train track beam and column during the experiment. It will not affect the flow field around the high-speed train. By significantly delaying the separation of airflow, it greatly reduces the size of the wake vortex, and ultimately reduces the aerodynamic noise generated by the wake vortex of the beam and column. This reduces the measurement error of the aerodynamic noise of the high-speed train and greatly improves the measurement accuracy of the wind tunnel experiment. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the first type of bridge beam and column structure used in wind tunnel experiments using existing technology.

[0019] Figure 2 This is a schematic diagram of the second type of bridge beam and column structure used in existing wind tunnel experiments.

[0020] Figure 3 This is a schematic diagram of the third type of bridge beam and column structure used in existing wind tunnel experiments.

[0021] Figure 4 This is a schematic diagram of the bridge beams and columns in the wind tunnel experiment of Example 1.

[0022] Figure 5 This is a cross-sectional view of the bridge beams and columns in Example 1.

[0023] Figure 6 This is a three-dimensional structural diagram of the bridge used for wind tunnel experiments in Example 2.

[0024] Figure 7 This is a three-dimensional structural diagram of the bridge used for wind tunnel experiments in Comparative Example 1.

[0025] Figure 8 yes Figure 6 A magnified view of part A in the image.

[0026] Figure 9 This is a cross-sectional view of the maglev train track beam used for wind tunnel experiments in Example 2.

[0027] Figure 10 yes Figure 9 A magnified view of part B in the image.

[0028] Figure 11 This is a longitudinal section view of the maglev train track beam used for wind tunnel experiments in Example 2.

[0029] Figure 12 yes Figure 11 A magnified view of part C.

[0030] Figure 13 This is a schematic diagram of the airflow guiding effect of the maglev train track beam used in wind tunnel experiments according to the present invention.

[0031] Figure 14 This is a pressure cloud diagram of the bridge section in the height direction in Example 1.

[0032] Figure 15 This is a velocity cloud diagram of the bridge section in the height direction in Example 1.

[0033] Figure 16 This is the vorticity diagram from Example 1.

[0034] Figure 17 This is a top view of the vorticity in Example 1.

[0035] Figure 18 This is a pressure cloud diagram of the bridge section in the height direction in Comparative Example 1.

[0036] Figure 19 This is a velocity contour map of the bridge section in the height direction in Comparative Example 1.

[0037] Figure 20 This is the vortex diagram in Comparative Example 1.

[0038] Figure 21 This is a top view of vorticity in scale 1.

[0039] Figure 22 This is a pressure cloud diagram of the bridge section in the height direction in Comparative Example 2.

[0040] Figure 23 This is a velocity contour map of the bridge section in the height direction in Comparative Example 2.

[0041] Figure 24 This is the vortex diagram from Comparative Example 2.

[0042] Figure 25 This is a top view of vorticity in scale 2.

[0043] 1. Track beam body; 11. Top plate; 12. Side plate; 13. Bottom plate; 14. Guide structure; 141. Outer guide surface; 142. Inner guide surface; 2. Guide cavity; 3. Beam column; a. First end; b. Second end. Detailed Implementation

[0044] To facilitate understanding of the present invention, the present invention will be described more fully and in detail below with reference to the accompanying drawings and preferred embodiments, but the scope of protection of the present invention is not limited to the following specific embodiments.

[0045] Example 1:

[0046] like Figure 4 and Figure 5 As shown, the bridge used for wind tunnel experiments in this embodiment includes a track beam body 1 and beam columns 3. The track beam body 1 in this embodiment adopts an existing track beam structure.

[0047] In this embodiment, the cross-section of beam-column 3 is symmetrical along its axis. The cross-section of beam-column 3 is a flat teardrop shape that bulges outward from the middle and tapers inward at both ends. The middle and both ends are connected by smooth arcs to form a streamlined structure. The two ends of the cross-section of beam-column 3 are the first end a and the second end b, respectively. Both the ends of the first end a and the second end b are arc-shaped, and the radius of the arc at the end of the first end a is larger than the radius of the arc at the end of the second end b. Specifically, the cross-section of beam-column 3 bulges outward from the first end a to the second end b, and then tapers inward. The maximum bulge is located in the middle of the cross-section of beam-column 3 and is biased towards the first end a. The cross-section of beam-column 3 as a whole is a smooth and continuous streamlined shape.

[0048] In this embodiment, the cross-sectional length S of beam-column 3 is 7165.7, the width W is 864.9, and the end radius R of the second end b is 25.2.

[0049] In this embodiment, the axis of beam column 3 coincides with the axis of track beam body 1, and the first end a is set facing the windward side, that is, beam column 3 is located at the center of the transverse direction of track beam body 1.

[0050] In this embodiment, multiple beams and columns 3 are arranged at equal intervals, with the first end a of adjacent beams and columns 3 facing each other, or the second end b of adjacent beams and columns 3 facing each other. That is, the arrangement directions of adjacent beams and columns 3 are opposite.

[0051] Example 2:

[0052] like Figure 6 , Figures 8 to 13 As shown, the bridge used for wind tunnel experiments in this embodiment includes a track beam body 1 and beam columns 3. The beam columns 3 in this embodiment are the same as those in embodiment 1. The main difference lies in the track beam body 1.

[0053] In this embodiment, the track beam body 1 has a flow guide cavity 2 extending along its length. The flow guide cavity 2 connects the two ends of the track beam body 1 and forms a channel for airflow. Since the airflow can pass through the flow guide cavity 2, the track beam in this embodiment can reduce the influence of the leading edge of the track beam body 1 on the flow field from the decimeter scale to the millimeter scale, thereby shortening the distance between the train head and the leading edge of the track beam body 1 and reducing the influence of the boundary layer on the experimental results. Existing technologies use the width of the track beam as the characteristic length. After 8 to 10 times the characteristic length, the influence of the leading edge of the track beam body 1 is relatively small. At this time, the distance between the leading edge of the track beam body 1 and the head of the train is 2.4 to 3.0 meters (based on a 1:10 model). Even if the leading edge of the track beam body 1 is streamlined, this distance still needs to be 1.5 to 2.0 meters. In this embodiment, the track beam body 1 is provided with a flow guide cavity 2. The airflow passes through the flow guide cavity 2, and the influence on the train flow field is the thickness of the track beam body 1, which is 5 mm. Its influence range is 8 to 10 times the characteristic length. The distance between the leading edge of the track beam body 1 and the head of the train only needs to be 40 to 50 mm to effectively reduce the influence of turbulence.

[0054] After reducing the distance between the leading edge of the track beam body 1 and the train head, the boundary layer thickness on the upper surface of the track beam body 1 below the train head is significantly reduced. If the air density in the wind tunnel is 1.225 kg / m³... 3 The wind speed is 60 m / s. In the existing technology, when the distance x between the leading edge of the track beam body 1 and the train head is 2.0 m, according to the calculation formula of the negative layer of the flat plate... Assuming the streamlined shape of the leading edge of the track beam body 1 is perfect and boundary layer separation will not occur, the boundary layer thickness on the upper surface of the track beam body 1 under the train head is 3.5mm, and the distance between the bottom of the maglev train and the bridge is 18.75mm, so the boundary layer has blocked the gap. In this embodiment, the boundary layer thickness on the upper surface of the track beam body 1 under the train head is 0.55mm. Therefore, the track beam of this embodiment significantly reduces the impact of the boundary layer on the experimental test accuracy.

[0055] In this embodiment, the windward end of the track beam body 1 is a planar structure without any protrusions. Specifically, both ends of the track beam body 1 in this embodiment are planar, without any beveled surfaces to form protrusions, which reduces the length of the track beam body 1, helps to reduce the thickness of the boundary layer and the cantilever length, and improves the accuracy of experimental testing.

[0056] In this embodiment, the track beam body 1 includes a top plate 11, side plates 12, and a bottom plate 13. The top plate 11, side plates 12, and bottom plate 13 together form the track beam body 1 with a flow guiding cavity 2. The thickness of the top plate 11, side plates 12, and bottom plate 13 is 5mm. Specifically, the top plate 11 and bottom plate 13 are both flat plates, and the top plate 11 and bottom plate 13 are arranged in parallel. The width of the top plate 11 is greater than the width of the bottom plate 13. There are two side plates 12, which are symmetrically arranged with respect to the axis of the track beam. The side plates 12 are made into a specific shape. The side plates 12 include a maglev track functional area and a bending area. The maglev track functional area is connected to the top plate through a vertical side. One end of the bending area is connected to the maglev track functional area, and the other end of the bending area is connected to the bottom plate 13. The bending area has an overall concave shape. The two symmetrical side plates 12 have concave bending areas that form a shape that is narrow at the top and wide at the bottom. The structure of the track beam body 1 can better fit with the guide cavity 2, reduce airflow interference at the end, and help improve experimental accuracy.

[0057] In this embodiment, streamlined flow-guiding structures 14 are provided at the ends of the top plate 11, side plate 12, and bottom plate 13 along the thickness direction. The flow-guiding structure 14 includes an outer flow-guiding surface 141 and an inner flow-guiding surface 142. The inner flow-guiding surface 142 guides the airflow into the flow-guiding cavity 2, and the outer flow-guiding surface 141 guides the airflow outward from the flow-guiding cavity 2. The flow-guiding structure 14 is a rounded corner structure located at the ends of the top plate 11, side plate 12, and bottom plate 13, with the outer flow-guiding surface 141 and the inner flow-guiding surface 142 arranged symmetrically. Specifically, the outer flow-guiding surface 141 is located on the outer side, and the inner flow-guiding surface 142 is located on the inner side. The flow-guiding structure 14 is formed by rounding the corners of the windward end face of the track beam body 1, with the rounded corner radius being half the plate thickness. Figure 13 As shown, the flow field arrives at the front end of the track beam from the far end. Since the thickness of the plate structure constituting the track beam body 1 is only 5mm, and each plate front end uses a rounded-corner guide structure 14, the flow field separation phenomenon caused by the square structure at the front end of the wall (if the rounded-corner structure is not used, when the airflow blows to the end without the rounded-corner structure, part of the flow field will rise and part will flow downward) is eliminated. That is, when the flow field passes through the streamlined guide structure 14, it will smoothly enter the external space and the guide cavity 2 of the track beam along the upper and lower guide surfaces respectively. The guide structure 14 greatly reduces the interference of the track beam's own structural parameters and shape on the flow field, thereby ensuring the authenticity and accuracy of the flow field structure acting on the train.

[0058] In this embodiment, a test area for parking the maglev train model is provided on the track beam. The distance M from the starting point of the test area to the windward end face of the track beam body 1 is 40mm≤M≤50mm. In this embodiment, the distance L between the beam column 3 and the end of the track beam body 1 is 0.2m. The turntable of the wind tunnel has limited dimensions, and generally only the beam column 3 is allowed to be set within the turntable. Otherwise, the track beam cannot be tested in a deflected crosswind. Therefore, the distance between the beam column 3 and the end of the track beam body 1 is a cantilever support. The longer the cantilever, the more severe the shaking during the experiment. The shaking will generate a vertical velocity in the airflow above the bridge surface, causing changes in the flow field under the vehicle and introducing a large error in the measurement. Taking the existing technology model scale of 1:10 as an example, its cantilever is about 1.5 to 2.0 meters longer than that of this embodiment. Therefore, the rigidity of the track beam body 1 must be very large to reduce shaking. However, increasing the rigidity of the track beam body 1 will significantly increase the manufacturing, transportation, and installation costs. In this embodiment, the track beam body 1 has a short distance between its leading edge and the head of the train, and there is no need to set up a protruding inclined guide. Therefore, the overall length and cantilever length of the track beam are shortened, which can greatly reduce the vibration of the track beam and reduce manufacturing, transportation and installation costs.

[0059] The wind tunnel testing method for the maglev train in this embodiment uses the bridge described above for wind tunnel testing and includes the following steps.

[0060] S1. Place the maglev train model on the track beam body 1. The distance between the front of the maglev train model and the windward end face of the track beam body 1 is M, where 40mm≤M≤50mm.

[0061] S2. A wind speed test sensor is set on the outside of the track beam body 1 to test the wind speed distribution outside the track beam body 1. Specifically, wind speed test sensors are set at 10mm, 20mm, 30mm and 40mm behind the windward end of the track beam. The sensor is used to test the wind speed distribution outside the track beam cavity, and then analyze and obtain the boundary layer parameters between the front end of the train and the front end of the track beam.

[0062] S3. A wind speed sensor is installed in the flow guiding cavity 2 of the track beam body 1 to test the flow velocity distribution in the flow guiding cavity 2. Specifically, wind speed sensors are installed at the centroid of the cross-section of the track beam body 1 along the cavity direction, in the same position as in S2. In addition, wind speed sensors are installed at 1 / 3, 1 / 2, 2 / 3 of the track beam length and at the outlet position to test the flow velocity distribution in the cavity of the track beam, thereby analyzing the overall flow guiding effect of the cavity track beam.

[0063] S4. Install testing instruments inside the maglev train model, specifically force balances, pressure scanning valves, and other testing instruments.

[0064] S5. Turn on the wind tunnel fan, start the test equipment and software, and begin the experimental test.

[0065] The wind tunnel test method of this embodiment was used to test the maglev train model. Due to the use of the hollow track beam body 1, airflow can flow through the guide cavity 2, which reduces the influence of the leading edge end face of the track beam body 1 on the flow field of the track beam and improves the measurement accuracy. The length from the train head to the windward end face of the track beam body is very short, which can significantly reduce the thickness of the bridge boundary layer and also significantly reduce the length of the cantilever beams at the front and rear ends of the bridge, reducing bridge vibration and the impact on the flow field at the bottom of the train. At the same time, the structure of the bridge beams and columns has been optimized to avoid errors caused by aerodynamic noise generated by the wake vortices of the beams and columns. With the combined effect of the two, the experimental error can be minimized to the greatest extent and the measurement accuracy can be significantly improved.

[0066] Comparative Example 1:

[0067] like Figure 7 As shown, the bridge used for wind tunnel experiments in this comparative example includes the track beam body 1 and the beam column 3.

[0068] In this comparative example, beam and column 3 adopts the following... Figure 2 The double cylindrical beam column 3 is shown.

[0069] The track beam body 1 in this comparative example is the same as the track beam body 1 in Example 2.

[0070] Comparative Example 2:

[0071] like Figure 3 As shown, the bridge used for wind tunnel experiments in this comparative example includes the track beam body 1 and the beam column 3.

[0072] The beam-column 3 in this comparative example has a cross-section with semicircles at both ends and a rectangle in the middle.

[0073] The track beam body 1 in this comparative example is the same as the track beam body 1 in Example 1.

[0074] Using FLUENT analysis software, the resistance ratio of the bridge under simulated conditions for Example 1, Comparative Example 1, and Comparative Example 2 was 1:3:5.2. Furthermore, pressure contour maps, velocity contour maps, and vorticity maps at different locations are shown for Example 1, Comparative Example 1, and Comparative Example 2 under the same conditions. The vorticity map is displayed using Q-isosurfaces, and velocity is used for rendering. See [link to details] for further information. Figures 14-25As can be seen from the figure, the airflow disturbance of the single column in Comparative Example 2 is the greatest, generating the most unsteady wake vortices (see the vorticity diagrams of each embodiment or comparative example) and outer detached vortices (see the top view of the vorticity of each embodiment or comparative example). It has the greatest impact on the airflow around the train (see the pressure cloud diagram and velocity cloud diagram of the bridge height section in each embodiment or comparative example; the black box in the figure represents the range of 3 meters to the left and right of the train center), while the beam and column in Example 1 have much smaller impacts.

[0075] While the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the invention. Any person skilled in the art can make many possible variations and modifications to the technical solutions of the present invention, or modify them into equivalent embodiments, without departing from the scope of the present invention. Therefore, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention, without departing from the scope of the present invention, should fall within the protection scope of the present invention.

Claims

1. A bridge for wind tunnel experiments, characterized in that: It includes a track beam body (1) and a beam column (3), wherein the track beam body (1) is mounted on the beam column (3); The cross section of the beam-column (3) is symmetrical along the axis. The cross section of the beam-column (3) is a flat teardrop shape that bulges outward in the middle and shrinks inward at both ends. The middle and both ends are connected by smooth arcs to form a streamlined structure. The two ends of the cross section of the beam-column (3) are the first end (a) and the second end (b). The ends of the first end (a) and the second end (b) are both arc-shaped, and the arc radius of the first end (a) is greater than that of the arc radius of the second end (b). The axis of the beam column (3) coincides with the axis of the track beam body (1), and the first end (a) is set facing the windward side; The track beam body (1) has a guide cavity (2) extending along the length direction inside. The guide cavity (2) connects the two ends of the track beam body (1) and forms a channel for airflow. The windward end of the track beam body (1) is a planar structure without protrusions. The bridge is equipped with a test area for parking a maglev train model. The distance from the starting point of the test area to the windward end face of the track beam body (1) is M, 40mm≤M≤50mm.

2. The bridge for wind tunnel experiments according to claim 1, characterized in that: The beams and columns (3) are provided at equal intervals, with the first end (a) of adjacent beams and columns (3) facing each other, or the second end (b) of adjacent beams and columns (3) facing each other.

3. The bridge for wind tunnel experiments according to claim 1, characterized in that: The track beam body (1) includes a top plate (11), a side plate (12) and a bottom plate (13). The top plate (11), the side plate (12) and the bottom plate (13) enclose the track beam body (1) having the flow guide cavity (2). The ends of the top plate (11), the side plate (12) and the bottom plate (13) are provided with streamlined flow guide structures (14) along the thickness direction. The flow guide structure (14) includes an outer flow guide surface (141) and an inner flow guide surface (142). The inner flow guide surface (142) is used to guide the airflow to flow into the flow guide cavity (2), and the outer flow guide surface (141) is used to guide the airflow to flow out of the flow guide cavity (2).

4. The bridge for wind tunnel testing according to claim 3, characterized in that: The flow guiding structure (14) is a rounded corner structure located at the ends of the top plate (11), side plate (12) and bottom plate (13), and the outer flow guiding surface (141) and inner flow guiding surface (142) are arranged symmetrically.

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