A wind tunnel simulation test device for agroforestry protection

Abstract

The utility model belongs to the field of forestry protection, relates to a wind tunnel simulation test device for forestry protection. The device includes at least one roughness element unit, which includes a main body, a roughness element, a connecting element and a counterweight element. The main body is in the shape of a right triangular pyramid and is telescopic, and has three edges that meet at a right angle and are perpendicular to each other. The roughness element is located on the outer surface of at least one right angle face of the main body, and has a predetermined roughness. The connecting element is arranged on the edge of the face opposite the right angle to interact with other connecting elements and be joined together. The counterweight element is located inside the main body and increases the weight of the roughness element unit. The device of the utility model designs roughness element units that can be used individually or in combination, can flexibly adjust the size and shape of the roughness element according to different scaling ranges, and meets the simulation needs of different scaling and structural diversification test scenarios in the forestry environment.

Description

Technical Field

[0001] This utility model belongs to the field of agricultural and forestry protection, and specifically relates to a wind tunnel simulation test device for agricultural and forestry protection. Background Technology

[0002] Wind plays a significant role in agroforestry ecosystems. In-depth research into the interaction between wind and agroforestry systems, and the resulting optimization of shelterbelt configurations and wind-resistant cultivation measures, has become an urgent need to ensure food security and ecological stability. Wind tunnel simulation experiments are an important method for studying wind speed and windbreak effectiveness in agroforestry environments.

[0003] Due to friction, wind speeds decrease vertically closer to the ground; the relationship between wind speed and altitude is called the wind speed profile. In wind tunnel simulations, to ensure accuracy, geometric similarity (the model and the object being studied are scaled proportionally) and dynamic similarity (the wind loads at the same location on the model and the object being studied are consistent, which can be understood as the wind speed profiles being scaled proportionally) are required. To better meet experimental conditions, it is usually necessary to disturb the incoming airflow; rough elements and wedges are effective devices for achieving this disturbance.

[0004] In large-scale wind tunnel simulations in aerospace and other fields, a scaled-down test method is typically used to study parameters such as drag coefficient, stress load, and pressure distribution on the surface of the model object. This requires uniform and stable airflow, without the need for disturbance. In wind tunnel simulations in fields such as construction, the research focuses on the stress load on the model surface at a selected height, with less emphasis on the airflow at other locations on the model or above it.

[0005] The wind tunnel simulations in the aforementioned fields do not require high precision in fitting three-dimensional airflow characteristics, and do not necessitate simultaneous changes in the perturbation measures when the research object or experimental conditions change. However, in the agricultural and forestry fields, especially in wind tunnel simulations involving wind erosion protection measures such as shelterbelts and farmland, the research results are not limited to the model itself, but focus more on the wind speed and flow field structure characteristics of a wider area before and after the research object (e.g., a forest belt). Therefore, the accuracy requirements for wind speed profile fitting are much higher. Furthermore, the wind speed simulation environment in the agricultural and forestry fields is complex, with varying research object structures (e.g., forest belt configurations may be two rows per belt, three rows per belt, or other forms) and significant variations in forest belt height (different tree species or ages have different heights). When wind speed, research object structure, or model scaling changes, it is necessary to readjust the placement of roughness elements, wedges, and other measures to maintain dynamic similarity.

[0006] Patent CN204788886U discloses a portable rough element device for wind tunnels, comprising a square wooden block with a flat surface and square top and bottom surfaces; a cylindrical magnet is embedded in a circular groove at the bottom of the block, the lower part of the magnet being a circular boss with a radius smaller than the radius of the circular groove and protruding beyond the groove and the bottom plane of the block; a wooden cover plate, with the same height as the boss, the same side length as the bottom surface of the block, and a pre-drilled circular hole in the middle, is attached to the bottom of the block, the boss being embedded in the circular hole of the cover plate, making the bottom of the block flat, and the height of the cover plate plus the height of the block equal to the side length of the squares on the top and bottom surfaces of the block, making the entire device a cube. This rough element device suffers from insufficient adaptability to wind tunnels after the rough element structure is modified. Because magnets and other materials are added to the rough element, the bottom of the wind tunnel needs to be made of metal for it to be used, but in actual experiments, plastic sheets are usually laid down for easy model replacement, leading to stability issues with the rough element.

[0007] Patent CN203376138U discloses an automatic lifting rough element device for boundary layer wind tunnels. The device includes a lifting platform, a rough element fixed to the upper surface of the lifting platform, and a lifting assembly connected to the lower surface of the lifting platform. The lifting assembly consists of a reducer and motor, a commutator connected to the reducer, and a lifting mechanism connected to the commutator. This device achieves disturbance of airflow at different heights through the continuous automatic lifting and lowering of the rough element. However, in practice, the device can only disturb the airflow at the location of the rough element; after the rough element is lifted, the airflow below the device loses its disturbance capability.

[0008] In summary, traditional block-shaped roughness element devices suffer from problems such as limited shape and size, poor adjustability and adaptability, and limited scaling ratios for fitting. They are unable to cover the diverse structures and scaling requirements of simulated objects, and also limit the accuracy of profile simulation, thus failing to meet the needs of wind tunnel simulation experiments in the agricultural and forestry fields.

[0009] Therefore, there is an urgent need to develop a rough element device that can be flexibly combined and easily adjusted to better meet the simulation needs of complex and diverse test scenarios in agricultural and forestry wind tunnel experiments. Utility Model Content

[0010] The purpose of this invention is to solve the problems existing in the prior art and provide a wind tunnel simulation test device for agricultural and forestry protection.

[0011] According to one aspect of the present invention, a wind tunnel simulation test device for agricultural and forestry protection is provided, the device comprising at least one rough element unit, the rough element unit comprising: The main body is in the shape of a right-angled triangular pyramid and is telescopic. The main body has a first edge, a second edge, and a third edge that meet at the right-angle vertices and are perpendicular to each other. The length H of the first edge is greater than the lengths of the second edge and the third edge. A roughening element is located on the outer surface of at least one right-angled face including the first edge of the body, and the roughening element has a predetermined roughness to achieve effective disturbance of the airflow. A connecting element disposed on an edge of a face opposite a right angle, the connecting element being able to interact with other connecting elements and engage together; A counterweight element, located inside the main body, increases the weight of the rough element unit.

[0012] According to one embodiment of the present invention, in the contracted state, the length of the first edge is 5-8 cm, and the lengths of the second and third edges are 3-5 cm.

[0013] According to one embodiment of the present invention, the roughening element is a rough material attached to the outer surface of the body, and the roughening element makes the coefficient of friction of the outer surface greater than 0.45.

[0014] According to one embodiment of the present invention, the rough element is a rough outer surface integrally formed with the main body, and the coefficient of friction of the rough outer surface is above 0.45.

[0015] According to one embodiment of the present invention, the main body further comprises: The fourth edge connecting the first edge and the second edge; The fifth edge connecting the first edge and the third edge; The sixth edge connecting the second edge and the third edge; The surface enclosed by the fourth, fifth, and sixth edges is the surface opposite to the right angle, and a connecting element is provided at each end of the fourth, fifth, and sixth edges.

[0016] According to one embodiment of the present invention, the connecting element is a hook and loop fastener, and the two connecting elements located on the same edge are respectively a hook-on part and a loop-on part.

[0017] According to one embodiment of the present invention, the connecting element is a magnetic component, and the two connecting elements located on the same edge are respectively a magnetic component and a magnetic conductive component.

[0018] According to one embodiment of the present invention, the main body adopts a nested telescopic structure, which can be pulled and stretched along the direction of the first edge, and the length of the first edge can be extended to a maximum of 10~15cm.

[0019] According to one embodiment of the present invention, the main body has a cavity inside, and metal powder or metal block is placed in the cavity as a counterweight element.

[0020] According to one embodiment of the present invention, the wind tunnel simulation test device further includes a cuboid combined rough element formed by joining four rough element units together, each of the rough element units being joined to two other rough element units via the connecting element.

[0021] According to another aspect of the present invention, a wind tunnel simulation test method for agricultural and forestry protection is provided, the method employing the wind tunnel simulation test apparatus as described in any of the above embodiments and comprising the following steps: Step 1: Determine the scaling ratio between the actual agricultural and forestry environment to be simulated and the model; Step 2: Configure the corresponding rough element device layout based on the scaling ratio; Step 3: Assemble and place the rough element units according to the layout of the rough element device; Step 4: During the experimental phase, wind speeds at different heights along the central axis of the longitudinal section at the model placement location are measured, and the measured data are fitted using an exponential function. Step 5: Perform a correlation analysis between the measured data and the actual outdoor wind speed profile data. If the data meets the requirements, conduct a wind tunnel simulation experiment. Otherwise, readjust the position of the rough element and repeat steps 2-4 above.

[0022] According to one embodiment of the present invention, when the scaling ratio is 0 to 20 times, the rough element units or cuboid combination rough elements are laid out using shrunken rough element units or cuboid combination rough elements, with a total of 10 to 15 rows laid out. The interval between two adjacent rough element units or cuboid combination rough elements in the same row is 3H to 6H, the interval between two adjacent rows is 3H to 6H, and the distance between the last row of rough elements and the model placement point is greater than 1m. When the scaling ratio is 21 to 50 times, both shrunken rough element units and cuboid combined rough elements are used for layout. 3 to 5 rows of rough element units are placed in the upwind direction. The interval between two adjacent rough element units in the same row is 3H to 6H, and the interval between two adjacent rows is 3H to 6H. Then, 10 to 15 rows of cuboid combined rough elements are placed. The interval between two adjacent cuboid combined rough elements in the same row is 3H to 6H, and the interval between two adjacent rows is 3H to 6H. The distance between the position of the last row of rough elements and the model placement point is greater than 1m. When the scaling ratio is 51 to 100 times, three types of rough element elements are used: elongated wedge-shaped rough element elements, contracted rough element elements, and cuboid combined rough element elements. 3 to 5 wedge-shaped rough element elements are placed at the wind tunnel inlet, with a spacing of 3H to 6H between them. Then, 3 to 5 rows of contracted rough element elements are placed upwind. The first row of contracted rough element elements is 0.5 to 1m apart from the wedge-shaped rough element elements. The spacing between two adjacent elements in the same row of contracted rough element elements is 2H to 5H, and the spacing between two adjacent rows is 3H to 5H. Finally, 15 to 20 rows of cuboid combined rough element elements are placed, with a spacing between two adjacent elements in the same row of cuboid combined rough element elements and a spacing between two adjacent rows of cuboid combined rough element elements. The distance between the last row of rough element elements and the model placement point is greater than 1.5m. When the scaling factor exceeds 100, wedge-shaped rough element elements, contracted rough element elements, and cuboid combined rough element elements are used for layout. 4-6 wedge-shaped rough element elements are placed at the wind tunnel inlet, with a spacing of 2H-5H between them. Then, 6-8 rows of contracted rough element elements are placed upwind, with the first row of contracted rough element elements spaced 0.5-1m apart from the wedge-shaped rough element elements. The spacing between two adjacent elements in the same row of contracted rough element elements is 2H-4H, and the spacing between two adjacent rows is 2H-4H. Finally, 15-20 rows of cuboid combined rough element elements are placed, with the spacing between two adjacent elements in the same row of cuboid combined rough element elements being 2H-4H, and the spacing between two adjacent rows being 2H-4H. The distance between the last row of rough element elements and the model placement point is greater than 1.5m.

[0023] According to one embodiment of the present invention, when the model height exceeds 10cm, the cuboid combination rough elements closer to the model need to be stacked in two layers, wherein the double-layered part accounts for 50% to 60% of the total number of rows of cuboid combination rough elements, while the other rough elements remain unchanged.

[0024] According to one embodiment of the present invention, the wedge-shaped rough element units, contracted rough element units, or cuboid combination rough element units in the same row are arranged in the same way and at the same height.

[0025] According to one embodiment of the present invention, a wind tunnel simulation experiment is conducted only when the correlation between the measured data and the actual outdoor wind speed profile data is greater than 0.8.

[0026] The wind tunnel simulation test device for agricultural and forestry protection provided by this utility model has at least one of the following beneficial effects compared with the prior art: (1) The device of this utility model is designed with rough element units that can be used individually or in combination. The size and shape of the rough element can be flexibly adjusted according to different scaling ratios, which meets the simulation needs of different scaling ratios and structurally diverse test scenarios in agricultural and forestry environments, and improves the accuracy of simulation. (2) The device of this utility model has a rough element set outside the rough element unit to increase the rough element's ability to disturb the airflow and improve the turbulence intensity; (3) The rough element unit of this utility model has a built-in counterweight element, which can maintain its own stability by gravity under the test conditions of large wind speed without the need for complicated disassembly. (4) The rough element unit of this utility model can increase its height through an extended structure, thereby increasing the airflow disturbance capability at different heights, and can also be used as a wedge; (5) The wind tunnel simulation test method of this utility model provides a systematic simulation scheme for the complex situation of agricultural and forestry environment. It is finely designed for different scaling ratios, realizes accurate coverage of full-scale scaling ratios, improves the reliability of wind field simulation, and enhances the accuracy, efficiency and repeatability of the experiment. It provides effective technical support for the evaluation of wind protection benefits of ecological projects such as shelterbelts and farmland. Attached Figure Description

[0027] To better understand this invention, reference can be made to the embodiments shown in the following figures. Components in the figures are not necessarily drawn to scale, and related elements may be omitted, or in some cases the scale may have been enlarged to emphasize and clearly illustrate the novel features described herein. Additionally, as is known in the art, system components may be arranged differently. Furthermore, in the figures, the same reference numerals denote corresponding parts throughout several views.

[0028] Figure 1 A simplified structural diagram of a rough element unit according to an embodiment of the present invention is shown; Figure 2 A simplified structural diagram of a cuboid combined rough element according to an embodiment of the present invention is shown; Figure 3 A flowchart of a wind tunnel simulation test method for agricultural and forestry protection according to an embodiment of the present invention is shown; Figure 4 A schematic diagram of a wind tunnel simulation test layout according to an embodiment of the present invention is shown; Figure 5 A fitting graph of wind speed profile measurement data according to an embodiment of the present invention is shown. Detailed Implementation

[0029] It should be understood that the embodiments of the present invention shown in the exemplary embodiments are merely illustrative. Although only a few embodiments have been described in detail in this invention, those skilled in the art will readily recognize that various modifications are possible without substantially departing from the teachings of the present invention. Accordingly, all such modifications should be included within the scope of this invention. Other substitutions, modifications, variations, and deletions can be made to the design, operating conditions, and parameters of the following exemplary embodiments without departing from the spirit of the present invention.

[0030] The following describes embodiments of the present disclosure. However, it should be understood that the disclosed embodiments are merely examples, and other embodiments may take various alternative forms. The drawings are not necessarily drawn to scale; certain functions may be exaggerated or minimized to show details of particular components. Therefore, the specific structural and functional details disclosed herein should not be construed as limiting, but merely as a representative basis for teaching those skilled in the art to use the present invention in various ways. As will be understood by those skilled in the art, various features shown and described with reference to any of the drawings may be combined with features shown in one or more other drawings to produce embodiments not explicitly shown or described. The combinations of features shown provide representative embodiments for typical applications. However, various combinations and modifications of features consistent with the teachings of this disclosure may be desired for certain particular applications or implementations.

[0031] In this application, when an element or part is referred to as "on," "joined to," "connected to," or "coupled to" another element or part, that element or part may be directly joined, connected to, or coupled to the other element or part, or there may be an element or part intervening therebetween. Conversely, when an element is referred to as "directly on," "directly joined to," "directly connected to," or "directly coupled to" another element or part, there may be no element or part intervening therebetween. Other terms used to describe the relationship between elements should be interpreted in a similar manner.

[0032] A wind tunnel is a device that generates controlled airflow and is used in aerodynamic research in agriculture and forestry. Low-speed wind tunnels are mostly used for wind tunnel simulation experiments in agriculture and forestry. To ensure the reliability of wind tunnel experiments, two "similarity principles" must be adhered to: geometric similarity and aerodynamic similarity. Geometric similarity refers to creating a model identical to the field survey environment (such as trees of different heights and types) to ensure consistency between the wind tunnel experiment and the field survey as much as possible. Aerodynamic similarity means that the external conditions in the wind tunnel simulation environment should be as similar as possible, such as roughness. Due to the influence of the research object, the model is usually scaled down to different proportions during application. Therefore, to ensure the accuracy of experimental results, it is necessary to simulate the atmospheric boundary layer to meet the aerodynamic similarity conditions.

[0033] Atmospheric boundary layer simulation primarily focuses on wind speed profile simulation. Currently, scholars both domestically and internationally have conducted extensive research on how to simulate high-quality incoming winds, employing methods that can be categorized into active and passive simulations, with roughness elements being a common application. By altering the placement and number of roughness elements, atmospheric boundary layers in different terrains can be effectively simulated.

[0034] In practical applications, when the scale of the wind tunnel experiment, the wind speed, or the object of study changes, the roughness elements need to be reconfigured. However, existing rotary and plate-type roughness elements are difficult to modify. In addition, traditional blocky roughness elements have limited scaling capabilities for fitting due to their uniform size, resulting in low accuracy.

[0035] To address the problems in the prior art, one aspect of this utility model provides a wind tunnel simulation test device for agricultural and forestry protection, the device comprising at least one rough element unit. The rough element unit includes: The main body is a right-angled triangular pyramid that can expand and contract. The main body has a first edge, a second edge, and a third edge that meet at the right-angle vertices and are perpendicular to each other. The length H of the first edge is greater than the lengths of the second and third edges. A rough element is located on the outer surface of at least one right-angled face of the body, including the first edge, and has a predetermined roughness to achieve effective disturbance of the airflow. Connecting elements are disposed on the edge of the face opposite to the right angle, and the connecting elements can interact with other connecting elements to join together; The counterweight element is located inside the main body and increases the weight of the rough element.

[0036] Existing rough element units (rough elements) have outer surfaces that are essentially the material's own surface, limiting their disturbance capabilities. This invention's rough element unit incorporates a roughened surface on the material's outer surface, increasing its ability to disturb airflow and enhancing turbulence intensity. Existing rough element units have simple structures, resulting in limited fitting effects. This invention's rough element unit, through the combined application of multiple structures, can improve the scaling range and fitting accuracy. Existing rough elements lack counterweights, relying primarily on adhesive bonding for fixation under high wind speed conditions, leading to complex disassembly. This invention's rough element unit incorporates high-density material, utilizing gravity for stability and facilitating movement when changing the rough element layout.

[0037] Figure 1 A simplified structural diagram of a rough element unit according to an embodiment of the present invention is shown. As shown, the main body 10 of the rough element unit is a right-angled triangular pyramid. Angle V is a right angle, and the three edges VA, VB, and VC intersect at point V, with each edge VA, VB, and VC being perpendicular to the others. Accordingly, the rough element unit includes three right-angled faces AVB, AVC, and BVC, one acute-angled triangular face ABC, and six edges VA, VB, VC, AB, AC, and BC. All of the aforementioned faces and edges have corresponding solid structures.

[0038] Among the three edges VA, VB, and VC that intersect at point V, edge VA is the longest, with a length of H. When the rough element is used alone, the face BVC perpendicular to edge VA is usually used as the bottom surface, and the direction of edge VA is the height direction of the rough element.

[0039] Optionally, in another embodiment, the three right-angled faces AVB, AVC, and BVC of the main body of the rough element have solid structures, while the face corresponding to the acute triangle ABC does not have a solid structure. That is, the rough element is generally composed of three right-angled faces and a counterweight element disposed within the space enclosed by the three right-angled faces; its acute-angled faces are actually open structures, such as openings. This saves materials and reduces costs.

[0040] In some embodiments, in the contracted state, the length of edge VA is 5-8 cm, and the lengths of edges VB and VC are 3-5 cm, wherein the lengths of edges VB and VC can be the same or different. In a specific embodiment, the length of edge VA is 5 cm, the length of edge VB is 4 cm, and the length of edge VC is 3 cm. The length, width, and height of the cuboid rough element assembled from the four rough element units are 3 cm, 4 cm, and 5 cm, respectively. Therefore, the rough element units can be spliced ​​into units of different sizes according to the length of the wind tunnel cross-section, allowing the width of its windward face to be flexibly adjusted within the range of 3-10 cm to meet various simulation requirements.

[0041] In some embodiments, the telescopic structure of the main body 10 is a nested telescopic structure. For example, the main body 10 includes multiple nested right-angled triangular pyramids, similar to multiple stacked sleeves. When multiple inner triangular pyramids are pulled outward along the VA direction, the main body 10 extends along the VA direction, and the length of the VA can extend up to 10-15 cm. When in the contracted state, only the upper part of each inner triangular pyramid is partially exposed, forming a gradually increasing conical top. Adjacent triangular pyramids can be fixed in the extended state by friction fit or elastic locking elements. When wedge-shaped rough elements are required, the inner triangular pyramids can be pulled out layer by layer to the fully extended state.

[0042] To increase the perturbation capability of the rough element on the airflow and improve the turbulence intensity, at least one right-angled surface (generally a non-bottom surface, in this embodiment, a surface AVC) of the main body 10 is provided with a rough element 12 on its outer surface. The rough element 12 has a predetermined roughness to achieve effective perturbation of the airflow. In one embodiment, the rough element 12 is a rough material attached to the outer surface of the main body 10, and the rough element 12 makes the coefficient of friction of the outer surface greater than 0.45. The rough material can specifically be sandpaper, nylon fiber, corrugated cardboard, etc. In another embodiment, the rough element 12 is a rough outer surface integrally formed with the main body 10, and the coefficient of friction of the rough outer surface is greater than 0.45. For example, the desired rough surface can be machined on the outer surface of the main body 10 by grinding, sandblasting, or other processing methods.

[0043] To achieve accurate coverage at full-scale scaling, it is sometimes necessary to change the shape of the rough element. This invention utilizes multiple rough element units to form a cuboid combined rough element. To achieve the connection between different rough element units, in some embodiments, connecting elements 14 are provided at the edge of the acute-angled triangular face ABC of the main body 10. For example... Figure 1 As shown, each end of edges AB, AC and BC is provided with a connecting element 14.

[0044] In some embodiments, the connecting element 14 is a hook and loop fastener (i.e., the Velcro commonly used in daily life). Two connecting elements 14 located on the same edge respectively adopt a hook surface and a rough surface. When two rough element units are mated, the hook surface of one rough element unit cooperates with the rough surface of the other rough element unit to form a tight connection. The hook surface and the rough surface can be fixed to the edge by means of bonding, welding or other methods.

[0045] In some embodiments, the connecting element 14 is a magnetic element, and two connecting elements 14 located on the same edge respectively employ a magnetic element and a magnetic conductor. Specifically, the magnetic element can be a permanent magnet, such as a neodymium iron boron magnet, and the magnetic conductor can be a magnetic element made of iron, nickel, cobalt, or their alloys. When two rough element units are mated, the magnetic element of one rough element unit engages with the magnetic conductor of the other rough element unit, thereby achieving magnetic bonding. The magnetic element and the magnetic conductor can be fixed to the edge by bonding or embedded within the edge.

[0046] Figure 2 A simplified structural diagram of a cuboid-shaped rough element according to an embodiment of the present invention is shown. This cuboid-shaped rough element is composed of four right-angled triangular pyramid rough element units. The right angle of each rough element unit corresponds to a right angle of the cuboid. The three mutually perpendicular edges of each rough element unit represent the length, width, and height of the cuboid where they intersect at a vertex. The three sides of the acute triangle of each rough element unit represent the diagonals of three adjacent faces of the cuboid. If the length of edge VA of the rough element unit is 5cm, the length of edge VB is 4cm, and the length of edge VC is 3cm, the length, width, and height of the cuboid rough element assembled from the four rough element units are 3cm, 4cm, and 5cm, respectively. When the scaling ratio is large, or the model height exceeds 10cm, the last few rows of cuboid rough elements near the model can be stacked in double layers. Stacking along different length, width, and height directions can form different heights of 6-10cm, thereby achieving flexible adjustment of different heights from 3-10cm and achieving precise coverage of the full-scale scaling ratio.

[0047] Continue to refer to Figure 1 To improve the stability of the right-angled triangular pyramid rough element unit under high wind conditions, in some embodiments of this invention, a counterweight element 16 is provided inside the main body 10. For example, the main body 10 may have a cavity inside, which is filled with metal powder or a metal block is installed as a counterweight element. With the built-in counterweight element, the rough element device can maintain its stability by gravity even under high wind speed test conditions, without the need for complex disassembly, and is also convenient to transport when rearranging.

[0048] This utility model also provides a wind tunnel simulation test method for agricultural and forestry protection. For example... Figure 3 As shown, the method employs the wind tunnel simulation test apparatus according to any of the above embodiments and includes the following steps: Step S1: Determine the scaling ratio between the actual agricultural and forestry environment to be simulated and the model; Step S2: Configure the corresponding rough element device layout based on the scaling ratio; Step S3: Assemble and place rough element units according to the layout of the rough element device; Step S4: During the test phase, the wind speed at different heights at the centerline of the longitudinal section where the model is placed is measured, and the measured data is fitted according to an exponential function; Step S5: Perform correlation analysis between the measured data and the actual outdoor wind speed profile data. If the data meets the requirements, conduct a wind tunnel simulation experiment. Otherwise, readjust the position of the rough element and repeat steps S2-S4 above.

[0049] Specifically, the layout of the rough element device based on the scaling ratio configuration includes: When the scaling ratio is 0 to 20 times, use shrunken rough element units or cuboid combination rough elements for layout, with a total of 10 to 15 rows. The interval between two adjacent rough element units or cuboid combination rough elements in the same row is 3H to 6H, the interval between two adjacent rows is 3H to 6H, and the distance between the last row of rough elements and the model placement point is greater than 1m. When the scaling ratio is 21 to 50 times, both shrunken rough element elements and cuboid combined rough elements are used for placement. 3 to 5 rows of rough element elements are placed in the upwind direction. The interval between two adjacent rough element elements in the same row is 3H to 6H, and the interval between two adjacent rows is 3H to 6H. Then, 10 to 15 rows of cuboid combined rough elements are placed. The interval between two adjacent cuboid combined rough elements in the same row is 3H to 6H, and the interval between two adjacent rows is 3H to 6H. The distance between the last row of rough element positions and the model placement point is greater than 1m. When the scaling ratio is 51 to 100, three types of rough element elements are used: elongated wedge-shaped rough element elements, contracted rough element elements, and cuboid combined rough element elements. 3 to 5 wedge-shaped rough element elements are placed at the wind tunnel inlet, with a spacing of 3H to 6H between them. Then, 3 to 5 rows of contracted rough element elements are placed upwind. The first row of contracted rough element elements is 0.5 to 1m apart from the wedge-shaped rough element elements. The spacing between two adjacent elements in the same row of contracted rough element elements is 2H to 5H, and the spacing between two adjacent rows is 3H to 5H. Finally, 15 to 20 rows of cuboid combined rough element elements are placed, with a spacing between two adjacent elements in the same row of cuboid combined rough element elements and a spacing between two adjacent rows of cuboid combined rough element elements. The distance between the last row of rough element elements and the model placement point is greater than 1.5m. When the scaling factor exceeds 100, wedge-shaped rough element elements, contracted rough element elements, and cuboid combined rough element elements are used for layout. 4-6 wedge-shaped rough element elements are placed at the wind tunnel inlet, with a spacing of 2H-5H between them. Then, 6-8 rows of contracted rough element elements are placed upwind, with the first row of contracted rough element elements spaced 0.5-1m apart from the wedge-shaped rough element elements. The spacing between two adjacent elements in the same row of contracted rough element elements is 2H-4H, and the spacing between two adjacent rows is 2H-4H. Finally, 15-20 rows of cuboid combined rough element elements are placed, with the spacing between two adjacent elements in the same row of cuboid combined rough element elements being 2H-4H, and the spacing between two adjacent rows being 2H-4H. The distance between the last row of rough element elements and the model placement point is greater than 1.5m.

[0050] By refining the design for different scaling ratios, accurate coverage of the full-scale scaling ratio was achieved, which improved the reliability of wind field simulation, enhanced the accuracy, efficiency and repeatability of the experiment, and provided effective technical support for the evaluation of wind protection benefits of ecological projects such as shelterbelts and farmland.

[0051] Figure 4 A schematic diagram of a wind tunnel simulation test layout according to an embodiment of the present invention is shown. The layout is designed for scaling ratios of 51 to 100 times. A row of three wedge-shaped rough element units is arranged at the wind tunnel inlet, followed by three rows of triangular pyramid-shaped rough element units (in a contracted state), and then 16 rows of cuboid combined rough elements are arranged.

[0052] In some embodiments, when the model height exceeds 10cm, the cuboid combined rough elements closer to the model need to be stacked in two layers, with the double-layered portion comprising 50% to 60% of the total number of rows of cuboid combined rough elements, while the other rough elements remain unchanged. Specifically, taking a scaling ratio exceeding 100 times and a model height exceeding 10cm as an example, using 18 rows of cuboid combined rough elements, the placement of wedge-shaped and pyramidal rough element units remains unchanged, as does the placement of the first 7 to 9 rows of cuboid combined rough elements. The last 9 to 11 rows of cuboid combined rough elements are placed in two layers per row.

[0053] In some embodiments, the wedge-shaped rough element units, contracted rough element units, or cuboid combination rough element units in the same row are arranged in the same way and at the same height.

[0054] In some embodiments, after the rough elements are deployed, during the experimental phase, the model is placed in a wind tunnel, and the wind speed at different heights (e.g., 0~10H) at the midline of the longitudinal section where the model is placed is measured. The measured data are then fitted using an exponential function, and the fitted R0 is obtained. 2The correlation coefficient should be no less than 0.8. Subsequently, the measured data and the actual outdoor wind speed profile data are correlated. If the correlation is no less than 0.8, a wind tunnel simulation experiment can be conducted; otherwise, the position of the roughness element needs to be readjusted and the above steps repeated.

[0055] Figure 5 A fitted graph of wind speed profile measurement data according to an embodiment of the present invention is shown. In this embodiment, wind speeds at heights of 0m, 1m, 2m, 4m, 6m, 8m, and 10m were measured at the centerline of the longitudinal section where the model was placed, and the measured data were fitted using an exponential function. The correlation R of the measured data in this embodiment is... 2 The value is 0.951, which meets the experimental requirements.

[0056] The above description is only a preferred embodiment of the present utility model and is not intended to limit the scope of implementation of the present utility model. Any modifications or equivalent substitutions to the present utility model without departing from the spirit and scope of the present utility model shall be covered within the protection scope of the present utility model.

Claims

1. A wind tunnel simulation test device for agricultural and forestry protection, characterized in that, It includes at least one rough element unit, the rough element unit comprising: The main body is in the shape of a right-angled triangular pyramid and is telescopic. The main body has a first edge, a second edge, and a third edge that meet at the right-angle vertices and are perpendicular to each other. The length H of the first edge is greater than the lengths of the second edge and the third edge. A roughening element is located on the outer surface of at least one right-angled face including the first edge of the body, and the roughening element has a predetermined roughness to achieve effective disturbance of the airflow. A connecting element disposed on an edge of a face opposite a right angle, the connecting element being able to interact with other connecting elements and engage together; A counterweight element, located inside the main body, increases the weight of the rough element unit.

2. The wind tunnel simulation test device for agricultural and forestry protection according to claim 1, characterized in that, In the contracted state, the length of the first edge is 5-8 cm, and the lengths of the second and third edges are 3-5 cm.

3. The wind tunnel simulation test device for agricultural and forestry protection according to claim 1, characterized in that, The roughening element is a rough material attached to the outer surface of the body, and the roughening element makes the coefficient of friction of the outer surface greater than 0.

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4. The wind tunnel simulation test device for agricultural and forestry protection according to claim 1, characterized in that, The rough element is a rough outer surface integrally formed with the main body, and the coefficient of friction of the rough outer surface is above 0.

45.

5. The wind tunnel simulation test device for agricultural and forestry protection according to claim 2, characterized in that, The subject also has: The fourth edge connecting the first edge and the second edge; The fifth edge connecting the first edge and the third edge; The sixth edge connecting the second edge and the third edge; The surface enclosed by the fourth, fifth, and sixth edges is the surface opposite to the right angle, and a connecting element is provided at each end of the fourth, fifth, and sixth edges.

6. The wind tunnel simulation test device for agricultural and forestry protection according to claim 5, characterized in that, The connecting element is a hook and loop fastener, and the two connecting elements located on the same edge are respectively a hook-on side and a loop-on side.

7. The wind tunnel simulation test device for agricultural and forestry protection according to claim 5, characterized in that, The connecting element is a magnetic component, and the two connecting elements located on the same edge are respectively a magnetic component and a magnetically conductive component.

8. The wind tunnel simulation test device for agricultural and forestry protection according to claim 2, characterized in that, The main body adopts a nested telescopic structure, which can be pulled and stretched along the direction of the first edge, and the length of the first edge can be extended to a maximum of 10~15cm.

9. The wind tunnel simulation test device for agricultural and forestry protection according to claim 1, characterized in that, The main body has a cavity inside, and metal powder or metal blocks are placed inside the cavity as counterweight elements.

10. The wind tunnel simulation test device for agricultural and forestry protection according to claim 1, characterized in that, The wind tunnel simulation test apparatus also includes a cuboid combined rough element formed by joining four of the rough element units together, each of the rough element units being joined to two other rough element units via the connecting element.

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