Forest belt layout design method for windproof efficiency of complex terrains

Abstract

The invention discloses a forest belt layout design method for the windproof efficiency of complex terrains. The problem that in the prior art, obvious limitation is shown when the complex terrains and diversified design requirements are met is solved. The method comprises the steps that a windbreak forest belt geometric model and an external fluid calculation domain are constructed, and then CFD simulation calculation is carried out to obtain a simulation result; calculating a windproof efficiency index according to a simulation result; then, optimizing forest belt structure parameters in combination with a complex actual application scene, and obtaining a final windbreak forest belt layout corresponding to the structural features; according to the method, the actual protection requirement under the complex terrain condition can be met, and finally the windbreak forest belt layout method with universality and adaptability is formed.

Description

Technical Field

[0001] The present invention relates to the technical fields of hydrodynamic simulation and environmental engineering, and particularly to a method for designing the layout of forest belts for wind protection efficiency in complex terrains. Background Art

[0002] Windbreak forest belts are an effective ecological protection measure and play an important role in agricultural and industrial areas as well as urban ecological protection by reducing wind speed, preventing sand dust diffusion, and improving microclimate conditions.

[0003] Traditional windbreak forest belt layout designs are usually based on empirical rules or local experiments. Although certain achievements have been made under some simple terrain conditions, the following limitations exist in practical applications: First, there is a lack of in-depth understanding of the airflow movement characteristics and wind field change laws around the windbreak forest belt, and it is impossible to quantitatively analyze the influence of the structural characteristics of the windbreak forest belt on the wind protection efficiency; Second, traditional designs often ignore the significant influence of terrain complexity on the wind field distribution, such as the airflow acceleration or flow separation phenomena on slopes and in valleys; Finally, in the face of special application requirements, traditional methods cannot flexibly adjust the structural characteristics of the windbreak forest belt to achieve the best protection efficiency. These deficiencies lead to obvious limitations of traditional methods in dealing with complex terrains and diverse design requirements. Summary of the Invention

[0004] The present invention provides a method for designing the layout of forest belts for wind protection efficiency in complex terrains, which solves the problem of obvious limitations in the prior art when dealing with complex terrains and diverse design requirements, realizes meeting the actual protection requirements under complex terrain conditions, and finally forms a general and adaptable method for designing the layout of windbreak forest belts.

[0005] The present invention provides a method for designing the layout of forest belts for wind protection efficiency in complex terrains, and the method includes:

[0006] S101, constructing a geometric model of the windbreak forest belt according to the structural characteristics of the windbreak forest belt, and determining the external fluid calculation domain of the geometric model of the windbreak forest belt; wherein, the geometric model of the windbreak forest belt is used to represent the structural characteristics of the windbreak forest belt; the external fluid calculation domain is used to represent the external terrain of the windbreak forest belt;

[0007] S102, performing simulation on the geometric model of the windbreak forest belt in the external fluid calculation domain based on an additional source term to obtain a simulation result;

[0008] S103, calculating a wind protection efficiency index according to the simulation result;

[0009] S104. Dynamically adjust the structural features of the windbreak belt geometric model to obtain different structural features of the windbreak belt. Repeat S101 to S103 to obtain the windproof efficiency indicators corresponding to different structural features. Screen the windproof efficiency indicators and determine the structural feature corresponding to the highest windproof efficiency indicator as the optimal structural feature;

[0010] S105. Adjust the optimal structural feature for the actual application scenario to obtain the adjusted structural feature;

[0011] S106. Construct a windbreak belt geometric model corresponding to the adjusted structural feature and perform simulation to obtain the adjusted simulation result, and further obtain the adjusted windproof efficiency indicator;

[0012] S107. Determine whether the adjusted windproof efficiency indicator meets the preset conditions. If it does not meet the preset conditions, dynamically adjust the adjusted structural feature until the adjusted windproof efficiency indicator meets the preset conditions to obtain the corresponding final structural feature; if it meets the preset conditions, use the adjusted structural feature as the final structural feature;

[0013] S108. Determine the layout of the windbreak belt corresponding to the final structural feature.

[0014] In a possible implementation, the constructing the windbreak belt geometric model according to the structural features of the windbreak belt includes:

[0015] Determine the structural features of the windbreak belt; wherein, the structural features include: the width of the windbreak belt, the porosity of the windbreak belt, the windbreak belt spacing, and the diversion angle of the windbreak belt;

[0016] Construct a windbreak belt geometric model according to the structural features of the windbreak belt.

[0017] In a possible implementation, the determining the external fluid calculation domain of the windbreak belt geometric model includes:

[0018] Perform mesh division on the external terrain of the windbreak belt geometric model to obtain the division result;

[0019] Determine the additional source term, turbulence model, and boundary conditions of the external terrain;

[0020] Determine the external fluid calculation domain of the windbreak belt geometric model according to the division result, additional source term, turbulence model, and boundary conditions.

[0021] In a possible implementation, the additional source term is expressed as:

[0022]

[0023] where μ represents the fluid viscosity coefficient; D i represents the i-th component of the viscous drag coefficient; u i represents the i-th component of the velocity; C i represents the i-th component of the inertial drag coefficient; ρ represents the air density; u represents the velocity.

[0024] In a possible implementation, simulating the geometric model of the windbreak in the external fluid calculation domain based on the additional source term to obtain simulation results includes:

[0025] Defining the windbreak area in the external fluid calculation domain as a porous medium domain, and determining the drag coefficient of the windbreak area according to the thickness of the porous medium and the porosity of the windbreak in the porous medium domain, and then obtaining the additional source term accordingly;

[0026] Obtaining the momentum equation with the additional source term according to the additional source term;

[0027] Determining the turbulence model and boundary conditions, and then performing simulation based on the porosity of the windbreak, the turbulence model and the boundary conditions to obtain the simulation results.

[0028] In a possible implementation, the porous medium characteristics of the porous medium domain are characterized by the Darcy - Forchheimer model.

[0029] In a possible implementation, the momentum equation is expressed as:

[0030]

[0031] where ρ represents the air density; u i represents the i-th component of the velocity; u j represents the j-th component of the velocity; f i represents the i-th component of the body force; x i represents the i-th component of the spatial coordinate; x j represents the j-th component of the spatial coordinate; S i represents the i-th component of the additional source term.

[0032] In a possible implementation, the turbulence model is the Reynolds-averaged Navier - Stokes model or the large eddy simulation model.

[0033] In a possible implementation, the boundary conditions include: the inlet mean wind profile, the synthetic turbulence inlet, the free outflow outlet, and the wall no-slip condition.

[0034] In a possible implementation, the wind protection efficiency indicators include: the wind speed profile, the relative wind speed, the normalized protection distance, and the normalized protection area, where:

[0035] The wind speed profile is generated by extracting the vertical wind speed distribution data in the simulation results;

[0036] The relative wind speed is calculated based on the wind speed at the reference position and the wind speed at the non-reference position in the simulation results;

[0037] Taking the height of the windbreak belt in the simulation results as a reference, the farthest distance at which the wind speed in the leeward area drops by 50% is calculated as the normalized protection distance;

[0038] Taking the height and length of the windbreak belt in the simulation results as a reference, the coverage area where the wind speed drops by 50% is evaluated as the normalized protection area.

[0039] One or more technical solutions provided in the present invention have at least the following technical effects or advantages:

[0040] In the present invention, by combining the fluid mechanics simulation technology with the additional source term, a high-precision simulation of the complex windbreak belt flow field structure is carried out. This method overcomes the difficulty of accurately depicting the geometric details of the windbreak belt in traditional Computational Fluid Dynamics (CFD) modeling, and at the same time can accurately simulate the influence laws of the windbreak belt on the wind speed, wind direction, and turbulence intensity; dynamically adjust the structural characteristics of the windbreak belt geometric model to obtain different structural characteristics of the windbreak belt, comprehensively analyze the influence of the structural characteristics of the windbreak belt geometric model on the wind field change, and quantitatively evaluate different schemes in combination with the wind protection efficiency index, breaking through the limitation that it is difficult to quantitatively evaluate the wind protection efficiency in the traditional empirical design method; adjust the optimal structural characteristics for the actual application scenario to obtain the adjusted structural characteristics, fully consider the influence of complex terrain on the air flow, and by adjusting the optimal structural characteristics, the wind speed control and efficient protection under complex terrain conditions can be realized, with applicability and design flexibility. Description of the Drawings

[0041] Figure 1 It is a flow chart of a method for designing the layout of a forest belt for wind protection efficiency facing complex terrain provided by an embodiment of the present invention;

[0042] Figure 2 It is a three-dimensional modeling schematic diagram of the windbreak belt and the external fluid calculation domain provided by an embodiment of the present invention;

[0043] Figure 3 It is a schematic diagram of the wind profile at different positions behind the windbreak belt provided by an embodiment of the present invention;

[0044] Figure 4 It is a schematic diagram of the influence of different windbreak belt widths on the protection area provided by an embodiment of the present invention;

[0045] Figure 5 Schematic diagram of the influence of different porosity of windbreak belts on the protected area provided by the embodiments of the present invention;

[0046] Figure 6 Curve of the influence of different spacings of windbreak belts on the relative wind speed provided by the embodiments of the present invention;

[0047] Figure 7 Schematic diagram of the influence of different deflection angles of windbreak belts on the protected area provided by the embodiments of the present invention;

[0048] Figure 8 Schematic diagram of the layout scheme of the windbreak belt at the site of the Omnidirectional Movable Radio Telescope (Qitai radio telescope, QTT) provided by the embodiments of the present invention. Detailed implementation manners

[0049] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0050] The present invention provides a method for designing the layout of forest belts for wind protection efficiency facing complex terrains. Refer to Figure 1 , the method includes:

[0051] S101, constructing a geometric model of the windbreak belt according to the structural characteristics of the windbreak belt, and determining the external fluid calculation domain of the geometric model of the windbreak belt; wherein, the geometric model of the windbreak belt is used to characterize the structural characteristics of the windbreak belt; the external fluid calculation domain is used to characterize the external terrain of the windbreak belt;

[0052] Specifically, in step S101, constructing a geometric model of the windbreak belt according to the structural characteristics of the windbreak belt includes the following steps S1011 to S1012.

[0053] S1011, determining the structural characteristics of the windbreak belt; wherein, the structural characteristics include: the width of the windbreak belt, the porosity of the windbreak belt, the spacing of the windbreak belt, and the deflection angle of the windbreak belt;

[0054] S1012, constructing a geometric model of the windbreak belt according to the structural characteristics of the windbreak belt.

[0055] Exemplarily, the geometric model of the windbreak belt can accurately reflect the structural characteristics of the windbreak belt, including width, porosity, spacing and deflection angle; the range of the external fluid calculation domain is set to a certain range upstream and downstream of the windbreak belt, and at the same time, the influence of the blockage ratio is considered to ensure that the development of the flow field is not restricted by the boundary conditions.

[0056] Specifically, in step S101, the external fluid calculation domain of the windbreak belt geometric model is determined, including:

[0057] (1) Mesh the external terrain of the windbreak belt geometric model to obtain the meshing result;

[0058] (2) Determine the additional source term, turbulence model and boundary conditions of the external terrain;

[0059] Here, the boundary conditions include: the inlet mean wind profile, synthetic turbulence inlet, free outflow outlet and wall no-slip condition.

[0060] (3) Determine the external fluid calculation domain of the windbreak belt geometric model according to the meshing result, additional source term, turbulence model and boundary conditions.

[0061] Exemplarily, the external terrain is divided into the near-surface area and the windbreak belt area, and the mesh sizes corresponding to the near-surface area and the windbreak belt area should be gradually refined to ensure the calculation accuracy.

[0062] Define the windbreak belt area as a porous medium domain, and use the Darcy-Forchheimer model to characterize the porous medium characteristics of the windbreak belt, that is, introduce an additional source term in the momentum equation to simulate the resistance effect of the airflow in the windbreak belt. Here, the additional source term is expressed as formula (1.1).

[0063] Set the turbulence model, such as the Reynolds-averaged Navier-Stokes (RANS) model or the large eddy simulation (LES) model. Among them, the RANS model is suitable for the simulation of steady flow fields, and the LES model can capture turbulent details more accurately, but the calculation cost is higher.

[0064] Set the boundary conditions, including the inlet mean wind profile, inlet turbulent boundary (which can be generated by the synthetic turbulence inlet method), outlet boundary, and wall no-slip condition.

[0065] S102, simulate the windbreak belt geometric model in the external fluid calculation domain based on the additional source term to obtain the simulation result.

[0066] It can be understood that the additional source term usually appears in the control equation in the form of a function. In the present invention, the mentioned additional source term is related to the inertial resistance coefficient C i The additional source term can simulate the blocking effect of the forest belt on the airflow, and there is no need to perform accurate geometric modeling for the complex shapes of each tree or branch and leaf, thus saving the simulation time and being beneficial to the research of different wind speed conditions, terrain changes and forest belt structure forms.

[0067] The simulation results mentioned here are the wind speed distributions at various positions in the external fluid calculation domain after passing through the geometric model of the windbreak belt.

[0068] Here, the additional source term is expressed as:

[0069]

[0070] where μ represents the fluid viscosity coefficient; D i represents the i-th component of the viscous drag coefficient; u i represents the i-th component of the velocity; C i represents the i-th component of the inertial drag coefficient; ρ represents the air density; u represents the velocity.

[0071] Here, the viscous loss term -μD i u i can be neglected, and the inertial loss term represents the resistance per unit volume in the forest belt area.

[0072] Here, the inertial drag coefficient C i can be calculated through the porosity of the windbreak belt and the calculation formula is:

[0073]

[0074] where, represents the porosity of the windbreak belt. In actual engineering, the porosity of the forest belt is often obtained by the image processing method; d represents the thickness of the porous medium.

[0075] Specifically, in step S102, based on the additional source term, a simulation of the geometric model of the windbreak belt is carried out in the external fluid calculation domain to obtain the simulation results, including the following S1021 to S1023.

[0076] S1021, define the windbreak belt area in the external fluid calculation domain as a porous medium domain, and determine the drag coefficient of the windbreak belt area according to the thickness of the porous medium and the porosity of the windbreak belt in the porous medium domain, and then obtain the additional source term accordingly;

[0077] Here, the porous medium characteristics of the porous medium domain are characterized by the Darcy-Forchheimer model.

[0078] S1022, obtain the momentum equation with the additional source term according to the additional source term;

[0079] Here, the momentum equation is expressed as:

[0080]

[0081] where ρ represents the air density; ui represents the i-th component of velocity; u j represents the j-th component of velocity; f i represents the i-th component of body force; x i represents the i-th component of spatial coordinate; x j represents the j-th component of spatial coordinate; S i represents the i-th component of additional source term.

[0082] S1023. Determine the turbulence model and boundary conditions, and then perform simulation based on the porosity of the windbreak belt, the turbulence model, and the boundary conditions to obtain the simulation results.

[0083] Here, the turbulence model is the Reynolds-averaged Navier-Stokes model or the large-eddy simulation model.

[0084] S103. Calculate the wind protection efficiency index according to the simulation results;

[0085] Specifically, in step S103, the wind protection efficiency index includes: wind speed profile, relative wind speed, normalized protection distance, and normalized protection area, where:

[0086] Generate the wind speed profile by extracting the vertical wind speed distribution data in the simulation results;

[0087] Calculate the relative wind speed based on the wind speed at the reference location and the wind speed at the non-reference location in the simulation results;

[0088] Taking the height of the windbreak belt in the simulation results as the benchmark, calculate the farthest distance at which the wind speed in the leeward area drops by 50% as the normalized protection distance;

[0089] Taking the height and length of the windbreak belt in the simulation results as the benchmark, evaluate the coverage area where the wind speed drops by 50% as the normalized protection area.

[0090] Exemplarily, wind speed profile: The wind speed profile refers to the law of the wind speed changing with height in the vertical direction, which can intuitively evaluate the protection effect of the windbreak belt near the ground and its wind protection ability at higher positions. Extract the vertical wind speed distribution data from the ground to a certain height range (such as from the ground to 2 times the height H of the windbreak belt) and draw the wind speed profile, which can reflect the wind speed changes at different heights.

[0091] By monitoring the wind speed distribution at each monitoring point downstream, calculate the relative wind speed, which is defined as the ratio of the wind speed at a specific position downstream to the reference wind speed upstream of the windbreak belt. The calculation formula is:

[0092]

[0093] where S represents the relative wind speed, V represents the wind speed at the non-reference location, and V0 represents the reference wind speed.

[0094] Here, the wind speed at the non-reference location is the wind speed at a certain location downstream of the windbreak belt; the wind speed at the reference location is the reference wind speed at a certain location upstream of the windbreak belt.

[0095] The calculation of the normalized protection distance takes the height H of the windbreak belt as the reference standard, representing the relative distance of the influence range of the windbreak belt. For example, D 0.5 is the farthest distance corresponding to a 50% decrease in the wind speed at a certain height in the leeward area of the windbreak belt.

[0096] The normalized protection area takes the height H and length L of the windbreak belt as the reference standards, and is used to evaluate the overall protection ability of the windbreak belt. For example, A 0.5 is the protection area corresponding to a 50% decrease in the wind speed at a certain height in the leeward area of the windbreak belt.

[0097] S104. Dynamically adjust the structural characteristics of the windbreak belt geometric model to obtain different structural characteristics of the windbreak belt. Repeat S101 to S103 to obtain the wind protection efficiency indicators corresponding to different structural characteristics, screen the wind protection efficiency indicators, and determine the structural characteristics corresponding to the highest wind protection efficiency indicator as the optimal structural characteristics;

[0098] Exemplarily, change the width, porosity, spacing, and diversion angle of the windbreak belt, and use 3D modeling software to generate the windbreak belt models and fluid domains corresponding to different structural characteristics. Conduct CFD simulations of the windbreak belt under different structural characteristics, and combined with the simulation results, quantitatively analyze the influence of each structural characteristic on wind protection efficiency indicators such as the wind speed reduction rate and the normalized protection distance.

[0099] S105. Adjust the optimal structural characteristics according to the actual application scenario to obtain the adjusted structural characteristics;

[0100] Exemplarily, the design principles of the actual application scenario include:

[0101] For the wind protection requirements in open plain areas, the number of rows and spacing of the windbreak belt should be optimized. Arrange multiple rows of windbreak belts in the dominant wind direction to form a uniform and continuous wind speed weakening zone.

[0102] For sloping terrains, it is necessary to consider their slope and aspect. Priority should be given to arranging windbreak belts at the top of the windward slope to reduce the wind speed acceleration effect caused by ascending airflows.

[0103] In valleys or narrow terrains, set the arrangement direction of the windbreak belt so that it is perpendicular to the dominant wind direction, and at the same time appropriately increase the number of rows of the windbreak belt to suppress the phenomenon of increased wind speed caused by the canyon effect.

[0104] S106. Construct a windbreak belt geometric model corresponding to the adjusted structural characteristics and conduct simulations to obtain the adjusted simulation results, and then obtain the adjusted wind protection efficiency indicators;

[0105] Exemplarily, in the formulation of the windbreak belt layout plan, in combination with the above-mentioned complex terrain windbreak belt design principles, based on the influence law of structural characteristics on wind prevention efficiency, a group of structural characteristics of the windbreak belt are initially determined. Through CFD simulation analysis, it is judged whether the wind prevention efficiency index of this layout plan meets the requirements. If not, the structure of the windbreak belt is continuously adjusted, and the simulation process is repeated until a windbreak belt layout plan that meets the wind prevention requirements is formed.

[0106] S107, determine whether the adjusted wind prevention efficiency index meets the preset conditions. If it does not meet the preset conditions, dynamically adjust the adjusted structural characteristics until the adjusted wind prevention efficiency index meets the preset conditions to obtain the corresponding final structural characteristics; if it meets the preset conditions, use the adjusted structural characteristics as the final structural characteristics;

[0107] It can be understood that the preset conditions usually refer to whether the wind speed reduction in the target area meets the requirements.

[0108] S108, determine the windbreak belt layout corresponding to the final structural characteristics.

[0109] In a specific embodiment provided by the present invention, referring to Figure 2 , a geometric model of the windbreak belt and an external fluid calculation domain are constructed. The geometric model of the windbreak belt is based on the height H of the windbreak belt, L is the length of the windbreak belt, the height of the external fluid calculation domain is 8H, and the width is 40H, meeting the requirement that the blockage ratio is less than 5%. At the same time, to ensure the full development of the external fluid calculation domain, the distance between the windbreak belt and the inlet of the external fluid calculation domain is 20H, and the distance between the windbreak belt and the outlet of the external fluid calculation domain is 40H.

[0110] An additional source term is introduced into the momentum equation to simulate the resistance effect of the airflow in the windbreak belt, which can avoid the difficulties of windbreak belt modeling and mesh generation in traditional CFD simulations. In the Fluent software, the windbreak belt area is defined as a porous medium domain, and the resistance coefficient of the windbreak belt area is set. The terrain model is meshed using unstructured grids, a near-surface inflation layer is set, and the average quality of the grid cells is checked. The numerical simulation method uses the Reynolds-averaged N-S (RANS) equations, the turbulence model uses the realizable k-ε turbulence model (Realizable k-ε model), a pressure-based steady solver is used, the pressure-velocity coupling is processed by the semi-implicit method for pressure-coupled equations (SIMPLEC algorithm), the discretization format uses a second-order accuracy format, and the judgment criterion for simulation convergence is that each residual drops to 10 -3 Below.

[0111] The Tecplot software is used for post-processing the simulation results. By analyzing the distribution of the relative wind speed and the wind profile, the structure of the external fluid computational domain is studied. The wind speed data at the height of H / 2 is extracted to calculate the normalized protection distance and the normalized protection area of the windbreak belt. Relative wind speed: By monitoring the wind speed at each downstream position, the relative wind speed is calculated, which is defined as the ratio of the wind speed at a certain downstream position to the upstream reference wind speed, and is used to quantify the deceleration effect of the windbreak belt. Refer to Figure 3 , the wind speed distributions at the horizontal distances of 5H, 10H, 15H, and 20H behind the windbreak belt and at the height of 0 - 2H are extracted to analyze the reduction effect of the windbreak belt on the wind speed in different regions. Normalized protection distance: Taking the height H of the windbreak belt as a reference, the influence range when the wind speed drops to 50% is calculated (such as D 0.5 represents the farthest distance corresponding to a 50% wind speed drop). Normalized protection area: Based on the height H of the windbreak belt and the length L of the windbreak belt, the normalized protection area is calculated (such as A 0.5 represents the protection area corresponding to a 50% wind speed drop).

[0112] By changing the structure of the windbreak belt and repeating the above CFD simulation process, a comprehensive analysis of the structural characteristics of the windbreak belt is carried out, including the width, porosity, spacing, etc. of the windbreak belt, and the influence law of the structural characteristics of the windbreak belt on the wind protection efficiency is analyzed.

[0113] Width of the windbreak belt: Refer to Figure 4 , appropriately increasing the width of the windbreak belt can expand the protected area. However, after exceeding a certain critical value, with the increase of the width of the windbreak belt, the resistance of the windbreak belt to the airflow increases, and the phenomenon of flow around occurs on both sides and above the windbreak belt, increasing the area of the recirculation region behind the windbreak belt, resulting in a gradual decline in the protection effect of the windbreak belt.

[0114] Porosity of the windbreak belt: Refer to Figure 5 , an appropriate porosity (0.3 - 0.5) can balance the resistance and the ventilation effect to achieve the best protection effect. Too low porosity will cause the airflow to be almost completely blocked, resulting in a sudden drop in the wind speed and an increase in the recirculation region behind the windbreak belt. Too high porosity will cause most of the airflow to penetrate through the windbreak belt, only having a small reduction effect on the wind speed.

[0115] Spacing between windbreak belts: Refer to Figure 6 , adjusting the spacing between windbreak belts can achieve a gradual reduction effect of the wind speed in different regions. A smaller spacing between windbreak belts can strengthen the airflow blockage and enhance the wind protection efficiency in the near region behind the windbreak belt, but the protection ability in the far region is weak. Increasing the spacing between windbreak belts is beneficial for wind protection in the far region.

[0116] Deflection angle of the windbreak belt: Refer to Figure 7, the flow-around phenomenon on both sides of the windbreak can be weakened by adjusting the inclination angle of the windbreak, further increasing the protected area. Among them, when the diversion angle is 30°, the protection effect is the best. If the diversion angle is too large, the windward area of the windbreak will decrease, weakening the wind protection efficiency. Therefore, it is necessary to flexibly adjust the diversion angle design according to the terrain characteristics and wind field distribution.

[0117] Adjust and optimize the layout plan of the windbreak for different complex terrain factors in the actual application scenario.

[0118] (1) In the slope terrain, due to the ascending air flow causing a significant acceleration of the wind speed, the windbreak should be preferentially arranged in the middle section of the slope. This arrangement can effectively reduce the kinetic energy of the air flow before it enters the slope top, weakening the influence of the air flow on the leeward area of the windbreak.

[0119] (2) Since the canyon terrain will cause a significant increase in the wind speed, the following design principles are recommended in this terrain: Set the arrangement direction of the windbreak to be perpendicular to the dominant wind direction to maximize the reduction of the kinetic energy of the air flow in the canyon; appropriately increase the number of rows of the windbreak and adjust the spacing between the windbreaks to achieve multi-stage reduction of the air flow and suppress the local acceleration effect.

[0120] (3) Terrain elevation difference: Make reasonable use of the height difference of the undulating terrain. Plant the windbreak at a high place, which can increase the relative height between the windbreak and the protected area, enabling its protection efficiency to cover a larger downstream area and form a wider low-wind-speed area in the leeward area.

[0121] Taking the 110m aperture QTT site under construction in Qitai, Xinjiang as an example, see Figure 8 in Figure 8 a and Figure 8 b. Under the condition of northward incoming wind, the air flow is forced to gather in the narrow valley, resulting in an accelerated wind speed and forming a typical "canyon wind effect". Under the condition of southward incoming wind, due to the openness of the terrain on the south side and the acceleration effect of the distant mountain body, a wind speed sudden increase area appears in the southwest direction of the radio telescope. Design the windbreak layout according to the complex terrain characteristics of the site area. By adjusting the layout plan of the windbreak multiple times, the double-layer windbreak designed in the north valley can play a role in extending the effective wind protection distance, as shown in Figure 8 a; For the wind speed sudden increase area on the south side of the site, the 30° diversion angle arranged obliquely on both sides can weaken the backflow phenomenon and effectively increase the protected area. The wind speed at the QTT position drops by about 40%, as shown in Figure 8 b.

[0122] The present invention combines computational fluid dynamics (CFD) simulation technology with the additional source term method to perform high-precision simulation on the flow field structure of complex windbreak belts. This method overcomes the difficulty of accurately depicting the geometric details of windbreak belts in traditional CFD modeling and can accurately simulate the influence laws of windbreak belts on wind speed, wind direction, and turbulence intensity.

[0123] The present invention comprehensively analyzes the influence of different windbreak belt structural characteristics (such as width, porosity, spacing, diversion angle, etc.) on wind field changes and quantitatively evaluates different design schemes in combination with wind protection efficiency indicators (such as wind speed reduction rate, protection distance, and protection area), breaking through the limitation that it is difficult to quantitatively evaluate wind protection efficiency in traditional empirical design methods.

[0124] The present invention fully considers the influence of complex terrains (such as slopes, canyons, and variable terrains) on airflows. By adjusting the layout position, direction, and structural characteristics of windbreak belts, wind speed control and efficient protection under complex terrain conditions can be achieved, with applicability and design flexibility.

[0125] The present invention relates to a method for optimizing the layout design of windbreak belts. Through computational fluid dynamics (CFD) simulation technology combined with complex terrain factors, comprehensive analysis and optimized design of the windbreak belt layout are carried out. First, a fluid domain model of the windbreak belt is constructed. By reasonably setting the turbulence model, additional source terms, and boundary conditions, CFD simulation calculations are performed to comprehensively analyze parameters such as the width, porosity, and spacing of the windbreak belt, and wind protection efficiency indicators such as the relative wind speed, protection distance, and protection area of different layout schemes are obtained. Subsequently, the structural parameters of the windbreak belt are optimized in combination with terrain characteristics such as the slope of complex terrain and narrow terrain. Finally, a windbreak belt layout scheme that meets the requirements of a specific application scenario is formulated to achieve efficient wind protection. This method has the advantages of high efficiency, low cost, and strong adaptability, providing a scientific basis for windbreak forest construction.

[0126] The various embodiments in this specification are described in a progressive manner. For the same or similar parts between the various embodiments, reference can be made to each other. Each embodiment focuses on the differences from other embodiments.

[0127] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the present invention.

Claims

1. A method for designing the layout of forest belts for windbreak effectiveness in complex terrains, characterized in that, Including: S101, construct a geometric model of the windbreak belt according to the structural characteristics of the windbreak belt, and determine the external fluid calculation domain of the geometric model of the windbreak belt; wherein, the geometric model of the windbreak belt is used to characterize the structural characteristics of the windbreak belt; the external fluid calculation domain is used to characterize the external terrain of the windbreak belt; S102, perform simulation on the geometric model of the windbreak belt in the external fluid calculation domain based on the additional source term to obtain a simulation result; S103, calculate the wind prevention efficiency index according to the simulation result; S104, dynamically adjust the structural characteristics of the geometric model of the windbreak belt to obtain different structural characteristics of the windbreak belt, repeat S101 to S103, obtain the wind prevention efficiency indexes corresponding to different structural characteristics, screen the wind prevention efficiency indexes, and determine the structural characteristic corresponding to the highest wind prevention efficiency index as the optimal structural characteristic; S105, adjust the optimal structural characteristic for the actual application scenario to obtain the adjusted structural characteristic; S106, construct a geometric model of the windbreak belt corresponding to the adjusted structural characteristic and perform simulation to obtain the adjusted simulation result, and further obtain the adjusted wind prevention efficiency index; S107, determine whether the adjusted wind prevention efficiency index meets the preset conditions. If it does not meet the preset conditions, then dynamically adjust the adjusted structural characteristic until the adjusted wind prevention efficiency index meets the preset conditions to obtain the corresponding final structural characteristic; if it meets the preset conditions, then use the adjusted structural characteristic as the final structural characteristic; S108, determine the layout of the windbreak belt corresponding to the final structural characteristic.

2. The method for designing the layout of forest belts for windbreak effectiveness facing complex terrains according to claim 1, wherein The constructing a geometric model of the windbreak belt according to the structural characteristics of the windbreak belt includes: Determine the structural characteristics of the windbreak belt; wherein, the structural characteristics include: the width of the windbreak belt, the porosity of the windbreak belt, the spacing of the windbreak belts, and the diversion angle of the windbreak belt; Construct a geometric model of the windbreak belt according to the structural characteristics of the windbreak belt.

3. The method for designing the layout of forest belts for windbreak effectiveness in complex terrains according to claim 1, characterized in that, The determining the external fluid calculation domain of the geometric model of the windbreak belt includes: Perform mesh division on the external terrain of the geometric model of the windbreak belt to obtain a division result; Determine the additional source term, turbulence model and boundary conditions of the external terrain; Determine the external fluid calculation domain of the geometric model of the windbreak belt according to the division result, additional source term, turbulence model and boundary conditions.

4. The method for designing the layout of forest belts for windbreak effectiveness in complex terrains according to claim 1, wherein The additional source term is expressed as: where μ represents the fluid viscosity coefficient; D i represents the i-th component of the viscous drag coefficient. Under high Reynolds number conditions, the viscous drag term can be neglected; C i represents the i-th component of the inertial drag coefficient; ρ represents the air density; u represents the velocity; u i represents the i-th component of the velocity.

5. The method for designing the layout of forest belts for windbreak effectiveness in complex terrains according to claim 1, wherein, The performing simulation on the geometric model of the windbreak belt in the external fluid calculation domain based on the additional source term to obtain a simulation result includes: Define the windbreak belt area in the external fluid calculation domain as a porous medium domain, and determine the resistance coefficient of the windbreak belt area according to the thickness of the porous medium and the porosity of the windbreak belt in the porous medium domain, and further obtain the additional source term according to...; Obtain the momentum equation with the additional source term according to the additional source term; Determine the turbulence model and boundary conditions, and then perform simulation based on the porosity of the windbreak belt, the turbulence model and the boundary conditions to obtain a simulation result.

6. The method for designing the layout of forest belts for windbreak effectiveness facing complex terrains according to claim 5, characterized in that, The porous medium characteristics of the porous medium domain are characterized by the Darcy - Forchheimer model.

7. The method for designing the layout of forest belts for windbreak effectiveness facing complex terrains according to claim 5, characterized in that, The momentum equation is expressed as: where ρ represents the air density; u i represents the i-th component of the velocity; t represents time; u j represents the j-th component of the velocity; f i represents the i-th component of the body force; x i represents the i-th component of the spatial coordinate; x j represents the j-th component of the spatial coordinate; S i represents the i-th component of the additional source term.

8. The method for designing the layout of forest belts for windbreak effectiveness in complex terrains according to claim 5, characterized in that, The turbulence model is the Reynolds-averaged Navier-Stokes model or the large eddy simulation model.

9. The method for designing the layout of forest belts for windbreak effectiveness in complex terrains according to claim 5, characterized in that, The boundary conditions include: the inlet mean wind profile, the synthetic turbulence inlet, the free outflow outlet, and the wall no-slip condition.

10. The method for designing the layout of forest belts for windbreak efficiency facing complex terrains according to claim 1, characterized in that, The wind protection efficiency indicators include: the wind speed profile, the relative wind speed, the normalized protection distance, and the normalized protection area, where: The wind speed profile is generated by extracting the vertical wind speed distribution data in the simulation results; The relative wind speed is calculated based on the wind speed at the reference location and the wind speed at the non-reference location in the simulation results; Based on the height of the windbreak belt in the simulation results, the farthest distance at which the wind speed in the leeward area drops by 50% is calculated as the normalized protection distance; Based on the height and length of the windbreak belt in the simulation results, the coverage area where the wind speed drops by 50% is evaluated as the normalized protection area.

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