CN114861263A - Method and system for finely simulating mountainous terrain wind speed field - Google Patents
Method and system for finely simulating mountainous terrain wind speed field Download PDFInfo
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Abstract
A method and a system for finely simulating a mountainous terrain wind speed field are disclosed, wherein the method comprises the steps of simplifying a mountain into a semi-ellipsoid structure which can be described in a parameterization manner and establishing a three-dimensional calculation model; establishing a foot cuboid calculation domain according to the size of the three-dimensional calculation model of the mountain; applying wind speed according with an exponential distribution rule to the entrance plane of the cuboid calculation domain through a turbulence model; observing the spatial distribution condition of the wind speed field in the cuboid calculation domain, extracting the wind direction angles and the wind speeds at different coordinates, searching the relation between the wind speed field and the mountain terrain parameters, and fitting by using a mathematical formula. The method can be used for analyzing the influence of mountainous terrain on wind speed compared with plain terrain, can research the negative influence of pressure and vortex force generated by local wind speed on capital construction projects established in mountainous areas by utilizing the advantage of higher wind speed discrimination at the positions close to the ground of mountains, and provides reference for mathematical quantification of wind field numerical simulation of complex terrain by nonlinear function fitting of wind speed field data.
Description
Technical Field
The invention belongs to the field of wind speed field simulation, and particularly relates to a method for finely simulating a mountainous terrain wind speed field.
Background
For the economic development field, the most basic is the utilization of energy, so the capital construction project related to energy transmission and information traffic is particularly important. When these infrastructure projects are put into operation, more or less complex non-flat terrain, such as mountainous areas, may be subjected locally to large wind loads, which is detrimental to the operational life of the infrastructure projects. Most of wind area diagrams given by the current meteorological bureau are rough, the wind speed of a certain area is considered from a macroscopic perspective, and sufficient obvious discrimination is not given to tens of meters of mountains running in a capital construction project close to the ground. Therefore, it is necessary to more finely simulate the wind speed field of the mountainous terrain and to distinguish the wind speed field according to the coordinate points.
Experimental studies are one of the most direct simulation methods. A large wind tunnel test device is used for establishing an equal-scale reduction model of a mountain area, and a control variable method is used for researching which size parameters of the mountain area have larger influence on a wind field. This process is particularly costly and difficult to operate. The other method is a method of simulation by using simulation software, the implementation is convenient, a mountain area model and a calculation domain can be realized by a two-dimensional model, and the defects are that the limitation is large, the incident wind direction angle cannot be adjusted as in the actual situation, the specific size of the wind speed value in each direction under a simulated three-dimensional coordinate system is low, the refinement degree is low, and the difference with an actual wind field is large.
Disclosure of Invention
The invention aims to provide a method for finely simulating a mountainous area terrain wind speed field, which aims to solve the problems in the prior art, optimizes three-dimensional calculation models of a mountainous area and a calculation domain by considering all terrain environment parameters of the mountainous area and the grid thickness condition of the surface of a mountain body, and realizes fine simulation of the wind speed field of a large field area of the whole mountainous area.
In order to achieve the purpose, the invention has the following technical scheme:
a method for finely simulating a mountainous terrain wind speed field comprises the following steps:
simplifying the mountain into a semi-ellipsoid structure which can be described in a parameterization way and establishing a three-dimensional calculation model;
establishing a cuboid calculation domain which is large enough according to the size of the three-dimensional calculation model of the mountain;
applying wind speed according with an exponential distribution rule to the entrance plane of the cuboid calculation domain through a turbulence model;
observing the spatial distribution condition of the wind speed field in the cuboid calculation domain, extracting the wind direction angles and the wind speeds at different coordinates, searching the relation between the wind speed field and the mountain terrain parameters, and fitting by using a mathematical formula.
Preferably, the step of simplifying the mountain into a semi-ellipsoid structure capable of being described in a parameterization manner and establishing the three-dimensional calculation model specifically includes:
converting the actual measured values of the real mountain area into parameters of mountain radius, mountain height, mountain distance and gradient for inputting;
according to the vegetation coverage degree of the mountain surface, the ground roughness is set to be 1.3-1.7 times of that of the flat ground.
Preferably, the building a cuboid calculation domain large enough according to the size of the three-dimensional calculation model of the mountain comprises:
setting the length of the cuboid calculation domain to be 8-12 times of the sum of the radius of the mountain and the distance between the mountains;
setting the width of the cuboid calculation domain to be 8-12 times of the radius of the mountain;
setting the height of the cuboid calculation domain to be 6-10 times of the height of the mountain;
setting the surfaces of the cuboid calculation domain except the speed inlet and the free outlet as standard wall functions without slippage;
and taking the part of the bottom surface of the cuboid calculation domain except the mountain area as a plain, dividing the plain into four types of landforms according to different actual environments, wherein each type of landform has a corresponding ground roughness length, and converting the numerical value of the ground roughness length multiplied by 20 times into a ground roughness height parameter to be input into finite element simulation software.
Preferably, the establishing of the cuboid calculation domain with a sufficient size according to the size of the three-dimensional calculation model of the mountain further comprises local encryption of the grid at the junction of the cuboid calculation domain and the three-dimensional calculation model of the mountain, so that the length of the grid is 1-2 meters.
Preferably, the roughness length of the ground is 0.01m, 0.05m, 0.3m and 1.0m corresponding to four types of landforms respectively.
Preferably, when the wind speed conforming to the exponential distribution rule is applied to the entrance plane of the cuboid calculation domain through the turbulence model, the turbulence model selects a readable k-epsilon model, the average wind speed at the height of 10m is taken as the basic wind speed, so that the relation between the speed and the height meets a Davenport exponential wind formula, and the wind speed vertically enters the entrance plane in a self-defined function form, and the expression is as follows:
in the formula (I), the compound is shown in the specification,
is the average wind speed and is the average wind speed,
the basic wind speed is adopted, y is the coordinate height, and alpha is the ground roughness coefficient;
the turbulence kinetic energy and the turbulence dissipation ratio of the incident wind speed are set in the form of a custom function, and the expression is as follows:
where k (y) denotes the kinetic energy of turbulence, V (y) denotes the velocity at height y, I (y) denotes the turbulence at height y, ε is the dissipation ratio of turbulence, L u (y) is the integral scale of turbulence, C u The value is 0.09, and K is 0.42; m is rice, y b Critical height of the segment, y, for turbulence g Is the gradient wind height.
Preferably, the basic wind speed is 25m/s-35 m/s.
Preferably, the ground roughness coefficient alpha and the gradient wind height y g And the piecewise critical height y of turbulence b Corresponding values of (a) correspond to four types of landforms and are respectively taken as follows:
the ground roughness coefficient alpha corresponding to the landform type A is 0.12, and the gradient wind height y g 300m, a piecewise critical height of turbulence y b Is 5 m;
the ground roughness coefficient alpha corresponding to the landform type B is 0.16, and the gradient wind height y g A critical height y of 350m, segment of turbulence b Is 5 m;
the ground roughness coefficient alpha corresponding to the landform type C is 0.22, and the gradient wind height y g A segment critical height y of 400m, turbulence b Is 5 m;
the ground roughness coefficient alpha corresponding to the landform type D is 0.30, and the gradient wind height y g 450m, a piecewise critical height of turbulence y b Is 10 m.
Preferably, the step of observing the cuboid to calculate the spatial distribution of the wind speed field in the domain, extracting the wind direction angles and the wind speeds at different coordinates, finding the relation between the wind speed field and the mountainous terrain parameters, and fitting by using a mathematical formula comprises:
extracting the speed and gradient of corresponding points, lines and surfaces according to the specific three-dimensional coordinates of the mountain positions of the infrastructure facilities;
and sorting the extracted corresponding points, lines and planes, namely the speed and gradient of the points, lines and planes, and the parameters corresponding to the three-dimensional calculation model of the mountain, performing nonlinear fitting by taking an exponential form with the base number of e as a frame, and verifying the convergence from the aspect of mathematics.
A mountain area topography wind speed field's simulation system that refines, characterized by includes:
the model building module is used for simplifying the mountain into a semi-ellipsoid structure which can be described in a parameterization way and building a three-dimensional calculation model;
the cuboid calculation domain building module is used for building a cuboid calculation domain which is large enough according to the size of a three-dimensional calculation model of a mountain;
the wind speed applying module is used for applying wind speed which accords with an exponential distribution rule to the entrance plane of the cuboid calculation domain through the turbulence model;
and the connection fitting module is used for observing the spatial distribution condition of the wind speed field in the cuboid calculation domain, extracting the wind direction angles and the wind speed at different coordinates, searching the connection between the wind speed field and the mountainous terrain parameters, and fitting by using a mathematical formula.
Compared with the prior art, the invention has the following beneficial effects:
the method for finely simulating the mountainous terrain wind speed field can analyze the influence of mountainous terrain on wind speed compared with plain terrain, refine grids and draw a finer wind area map. By utilizing the advantage of higher wind speed discrimination at the position of the mountain near the ground, negative influences of pressure and vortex force generated by local wind speed on capital construction projects (such as lightning rod towers, power transmission lines, bridges and the like) established in the mountain area can be researched, so that corresponding protective measures can be taken for potential risks. The fitting of a non-linear function on the wind speed field data also provides a reference for the mathematical quantification of the numerical simulation of the wind field in complex terrain.
Furthermore, the method of the invention considers various terrain parameter changes of the mountain, increases a turbulent flow viscosity formula, increases a transmission equation aiming at the dissipation rate, partially encrypts the grid at the position of the mountain near the ground infrastructure project, realizes the refined simulation of the wind speed field, and further improves the discrimination of the wind speed at different coordinates of the large field. The simulation method is used for simulating the wind speed field in the mountainous area where the actual capital construction project is located, the simulation speed can be obviously improved, the cost is reduced, the three-dimensional wind speed simulation precision of the whole calculation domain, particularly in the local range of the surface of the mountain body, is effectively improved, and a finer wind area graph can be drawn.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required to be used in the embodiments are briefly described below, it should be understood that the following drawings only show some embodiments of the present invention, and it is obvious for those skilled in the art that other related drawings can be obtained according to these drawings without creative efforts.
FIG. 1 is a schematic flow diagram of a refined simulation method of a mountainous terrain wind speed field;
FIG. 2 is a schematic diagram of a three-dimensional computational model of a mountain terrain in an embodiment of the present invention;
FIG. 3 is a schematic diagram of local encryption and refinement of mountain surface grids in an embodiment of the present invention;
FIG. 4 is a schematic diagram illustrating self-sustaining verification of wind speed according to an embodiment of the present invention;
FIG. 5 is a mountain wind speed cloud chart of the XY cross section of the calculated domain in the embodiment of the present invention;
FIG. 6 is a mountain area wind velocity vector diagram of a YZ cross section of a domain calculated in an embodiment of the present invention;
FIG. 7 is a diagram of a mountain area wind velocity vector diagram of a calculated domain XZ cross section in an embodiment of the present invention;
FIG. 8 is a graph showing the relationship between the wind speed and acceleration ratio of the mountain top and the height of a coordinate point, the radius of a mountain body, the distance between mountain bodies and the height of the mountain body in the embodiment of the invention;
FIG. 9 is a graph showing a relationship between a wind speed acceleration ratio of a valley and a coordinate point height, a mountain radius, a mountain distance and a mountain height in the embodiment of the present invention;
FIG. 10 is a graph showing the relationship between the vertical wind speed on the windward slope of the mountain surface and the height of the coordinate point, the height of the mountain and the slope of the mountain in the embodiment of the present invention.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, not all, embodiments of the present invention.
Based on the embodiments of the present invention, those skilled in the art can make several simple modifications and decorations without creative efforts, and all other embodiments obtained belong to the protection scope of the present invention.
Reference in the present specification to "an example" means that a particular feature, structure, or characteristic described in connection with the example may be included in at least one embodiment of the invention. The appearances of the phrase in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments. It is explicitly and implicitly understood by a person skilled in the art that the embodiments described in the present invention can be combined with other embodiments.
Referring to fig. 1, a method for refining a mountainous terrain wind speed field according to an embodiment of the present invention includes the following steps:
s1: the mountain approximation is regarded as an ellipsoid to establish a three-dimensional calculation model;
s2: establishing a cuboid calculation domain with the length, width and height being sufficiently larger than the size of the mountain model;
s3: selecting a proper turbulence model, and applying wind speed according with an exponential distribution rule to the plane of the inlet;
s4: observing the spatial distribution condition of the wind speed field through post-processing software, extracting the wind direction angles and the wind speeds at different coordinates, searching the relation between the wind speed field and the topographic parameters of the mountainous area, and fitting by using a mathematical formula.
In an optional embodiment, the step of building a three-dimensional computation model in step S1 specifically includes:
simplifying the mountain into a semi-ellipsoid structure capable of being described in a parameterization mode, and converting actual measured values of the mountain area into parameters such as mountain radius, mountain height, mountain distance and slope for inputting;
according to the vegetation coverage degree of the mountain surface, the ground roughness is set to be 1.3-1.7 times of that of the flat ground.
In an optional implementation, the step of creating a rectangular parallelepiped calculation domain in step S2 specifically includes:
in order to avoid the influence of the wall surface on the distribution of the wind speed field, the length of the cuboid calculation domain is set to be 8-12 times of the sum of the radius of the mountain and the distance between the mountains;
setting the width of the cuboid calculation domain to be 8-12 times of the radius of the mountain;
setting the height of the cuboid calculation domain to be 6-10 times of the height of a mountain;
setting the surfaces of the cuboid calculation domain except the speed inlet and the free outlet as standard wall functions without slippage;
taking the part of the bottom surface of the cuboid calculation domain except the mountain area as a plain, dividing the plain into four types of landforms according to the difference of actual environments, wherein each landform has a corresponding ground roughness length, and multiplying the value by 20 times to obtain a ground roughness height parameter which is input into finite element simulation software;
and local encryption of the grid is carried out on the junction of the calculation domain and the mountain model, so that the length of the grid is about 1-2 meters, and the three-dimensional wind speed of the mountain at different coordinates close to the ground can be extracted more finely.
Further, according to industry standards, the roughness of the ground can be classified into A, B, C, D four categories:
1. class A refers to offshore sea surface, island, coast, lakeshore and desert areas;
2. class B refers to fields, villages, jungles, hills, and rural and urban suburbs with sparser houses;
3. class C refers to urban areas with dense building groups;
4. class D refers to urban areas with dense building groups and tall houses.
Roughness length z of four kinds of landforms 0 The following values are taken correspondingly, specifically:
| landform category | Roughness length z 0 /m |
| A | 0.01 |
| B | 0.05 |
| C | 0.3 |
| D | 1.0 |
In an alternative embodiment, the turbulence model selected in step S3 is a Realizable k- ε model;
taking the average wind speed at the height of 10m as the basic wind speed, and actually measuring the average wind speed according to a meteorological bureau, wherein the average wind speed is generally 25-35 m/s;
the relation between the speed and the height meets the Davenport index wind formula, and the wind vertically enters the inlet face in the form of a user-defined function, wherein the formula is as follows:
in the formula (I), the compound is shown in the specification,
is the average wind speed and is the average wind speed,
the wind speed is the basic wind speed, y is the coordinate height, and alpha is the ground roughness coefficient, and can be selected according to different landforms;
the turbulence kinetic energy and the turbulence dissipation ratio of the incident wind speed are also set in the form of user-defined functions, and the formula is as follows:
where k (y) denotes the kinetic energy of turbulence, V (y) denotes the velocity at height y, I (y) denotes the turbulence at height y, ε is the dissipation ratio of turbulence, L u (y) is the integral scale of turbulence, C u The value is 0.09, and K is 0.42; m is rice, y b Critical height of the segment, y, for turbulence g Is the gradient wind height.
The turbulence model selection readable k-epsilon model has the following advantages:
the Navier-Stokes equation is an N-S equation for short, and is a motion equation for describing the conservation of the momentum of the viscous incompressible fluid;
the time average simplification processing is carried out on the N-S equation by introducing a Reynolds time-average simulation method, so that the calculation amount of a CPU (Central processing Unit) can be greatly reduced;
compared with a standard k-epsilon model, the Realizable k-epsilon model increases a turbulent viscosity formula, and increases a transmission equation aiming at the dissipation rate;
the readable k-epsilon model can accurately predict the occasions of rotating flow, boundary layer flow with strong inverse pressure gradient, flow separation and the like.
Furthermore, the ground roughness coefficient alpha and the gradient wind height y for the four landforms g And turbulenceCritical height y of degree segment b The corresponding values are as follows:
| landform category | Coefficient of roughness alpha | y g /m | y b /m |
| A | 0.12 | 300 | 5 |
| B | 0.16 | 350 | 5 |
| C | 0.22 | 400 | 5 |
| D | 0.30 | 450 | 10 |
In an alternative embodiment, the specific step of step S4 includes: drawing a wind speed vector diagram, a cloud diagram and the like in a large field, observing the change trend, searching for a rule, and providing a refined reference for a rough wind area diagram;
extracting the speed and gradient of corresponding points, lines and surfaces according to the specific three-dimensional coordinates of the mountain positions of the infrastructure facilities;
and sorting the extracted corresponding points, lines and planes, namely the speed and gradient of the points, lines and planes, and the parameters corresponding to the three-dimensional calculation model of the mountain, performing nonlinear fitting by taking an exponential form with the base number of e as a frame, and verifying the convergence from the aspect of mathematics.
In an embodiment of the present invention, the three-dimensional computation model of the specific mountain terrain is composed of a simplified parametrizable description semi-ellipsoid structure and a rectangular parallelepiped computation domain, as shown in fig. 2, and can be converted into parameters such as a mountain radius, a mountain height, a mountain distance, a slope and the like according to actually measured values of the mountain area for input. In this example, the ground roughness was set to 1.5 times as high as that in plain according to the vegetation coverage on the mountain surface. In the embodiment, the calculation domain length is 10 times of the sum of the radius of the mountain and the distance between the mountains, the width is 8 times of the radius of the mountain, the height is 7 times of the height of the mountain, the front surface and the rear surface of the cuboid are respectively set as a speed inlet and a free outlet, and the other surface is set as a standard wall surface function without slippage. The part of the bottom surface of the calculation domain except the mountain area is regarded as a plain, the plain is regarded as a B-type landform according to the actual environment, the corresponding ground roughness length is 0.05m, and the ground roughness height parameter can be obtained by multiplying the value by 20 times and then input into finite element simulation software.
The three-dimensional calculation model of the mountain terrain shown in fig. 2 is subjected to grid division before simulation, the grid length is taken as 5m for a general air domain, but the grid is locally encrypted at the junction of the calculation domain and the mountain model, so that the grid length of the mountain near the ground is 1m, and a foundation is laid for extracting three-dimensional wind speeds at different coordinates of the mountain near the ground in a subsequent more refined manner. The three-dimensional computation model after the whole computation domain and the mountain surface mesh are partially encrypted and refined is shown in fig. 3.
In order to accurately predict the occasions of rotating flow, boundary layer flow with strong adverse pressure gradient, flow separation and the like, the turbulence model of the embodiment selects a readable k-epsilon model, increases a turbulence viscosity formula, and increases a transmission equation aiming at the dissipation rate.
On the other hand, in the present embodiment, the average wind speed at a height of 10m is taken as the basic wind speed, and 25m/s is obtained from the results of actual measurement by the meteorological office. The incident wind speed meets Davenport index formula and is vertically incident to the inlet face, the ground roughness coefficient of the embodiment is 0.16 of that of the B-class landform, the turbulence kinetic energy and the turbulence dissipation rate of the incident wind speed are also set in the form of user-defined functions, and the gradient wind height y g And y b 350m and 5m respectively.
In order to verify the correctness of the setting of the boundary condition of the entrance, the present embodiment performs self-sustaining verification on the wind profile with the wind speed varying with the altitude, and proves that the wind profile does not undergo large-amplitude distortion after entering the calculation domain from the incident surface until the wind profile travels to the distance 2 times of the radius of the mountain in front of the mountain, and the simulated wind field in the mountain area cannot be considered to be completely changed from the incident time due to the shielding effect and the narrow-pipe effect of the mountain, as shown in fig. 4. In this embodiment, schematic diagrams such as a mountain wind speed cloud chart of an XY cross section of a calculation domain in a large field, a mountain wind speed vector chart of a YZ cross section of the calculation domain, and a mountain wind speed vector chart of an XZ cross section of the calculation domain are drawn, and the wind division is more detailed and is respectively shown in fig. 5, 6, and 7. In the embodiment, three key positions of a mountain top, a mountain valley and a mountain body windward slope are selected, the three-dimensional wind speed corresponding to the coordinate position is extracted, the three-dimensional wind speed is arranged together with parameters corresponding to a mountain body three-dimensional calculation model, fitting of a nonlinear function is carried out by taking an exponential form with the base number as e as a frame, convergence is verified from a mathematical angle, and reference is provided for mathematical quantification of numerical simulation of a wind field of a complex terrain.
The relationship between the wind speed acceleration ratio of the mountain top and the coordinate point height, the mountain radius, the mountain distance and the mountain height is shown in fig. 8, the relationship between the wind speed acceleration ratio of the valley and the coordinate point height, the mountain radius, the mountain distance and the mountain height is shown in fig. 9, and the relationship between the vertical wind speed of the windward slope on the surface of the mountain and the coordinate point height, the mountain height and the mountain slope is shown in fig. 10.
Another embodiment of the present invention further provides a system for refining simulation of a wind velocity field of a mountainous terrain, including:
the model building module is used for simplifying the mountain into a semi-ellipsoid structure which can be described in a parameterization way and building a three-dimensional calculation model;
the cuboid calculation domain establishing module is used for establishing a cuboid calculation domain which is large enough according to the size of the three-dimensional calculation model of the mountain;
the wind speed applying module is used for applying wind speed which accords with an exponential distribution rule to the entrance plane of the cuboid calculation domain through the turbulence model;
and the connection fitting module is used for observing the spatial distribution condition of the wind speed field in the cuboid calculation domain, extracting the wind direction angles and the wind speed at different coordinates, searching the connection between the wind speed field and the mountainous terrain parameters, and fitting by using a mathematical formula.
According to the method and the system for the refined simulation of the mountainous terrain wind speed field, various terrain parameter changes of a mountain are considered, a turbulent flow viscosity formula is added, a transmission equation is added aiming at the dissipation rate, the grids of the position of a mountainous ground infrastructure project are locally encrypted, the refined simulation of the wind speed field is realized, and the discrimination of the wind speeds at different coordinates of a large field is further improved; the simulation method is used for simulating the wind speed field in the mountainous area where the actual capital construction project is located, the simulation speed can be obviously improved, the cost is reduced, the three-dimensional wind speed simulation precision of the whole calculation domain, particularly in the local range of the surface of the mountain body, is effectively improved, and a finer wind area graph can be drawn. By utilizing the advantage of higher wind speed discrimination at the mountain near the ground, negative influences of pressure and vortex force generated by local wind speed on capital construction projects (such as lightning rod towers, power transmission lines, bridges and the like) established in the mountain area can be researched by a wind vibration response simulation analysis method, so that corresponding protective measures can be taken for potential risks. The fitting of a non-linear function on the wind speed field data also provides a reference for the mathematical quantification of the numerical simulation of the wind field in complex terrain.
It will be apparent to those skilled in the art that, for convenience and brevity of description, only the above-mentioned division of the functional units and modules is illustrated, and in practical applications, the above-mentioned function distribution may be performed by different functional units and modules according to needs, that is, the internal structure of the apparatus is divided into different functional units or modules to perform all or part of the above-mentioned functions. Each functional unit and module in the embodiments may be integrated in one processing unit, or each unit may exist alone physically, or two or more units are integrated in one unit, and the integrated unit may be implemented in a form of hardware, or in a form of software functional unit. In addition, specific names of the functional units and modules are only for convenience of distinguishing from each other, and are not used for limiting the protection scope of the present application. The specific working processes of the units and modules in the system may refer to the corresponding processes in the foregoing method embodiments, and are not described herein again.
The integrated unit, if implemented in the form of a software functional unit and sold or used as a stand-alone product, may be stored in a computer readable storage medium. Based on such understanding, all or part of the processes in the methods of the embodiments described above can be implemented by a computer program, which can be stored in a computer-readable storage medium and can implement the steps of the embodiments of the methods described above when the computer program is executed by a processor. Wherein the computer program comprises computer program code, which may be in the form of source code, object code, an executable file or some intermediate form, etc. The computer readable medium may include at least: any entity or device capable of carrying computer program code to a photographing apparatus/terminal apparatus, a recording medium, computer Memory, Read-Only Memory (ROM), Random Access Memory (RAM), an electrical carrier signal, a telecommunications signal, and a software distribution medium. Such as a usb-disk, a removable hard disk, a magnetic or optical disk, etc.
In the above embodiments, the descriptions of the respective embodiments have respective emphasis, and reference may be made to the related descriptions of other embodiments for parts that are not described or illustrated in a certain embodiment.
The above-mentioned embodiments are only used for illustrating the technical solutions of the present application, and not for limiting the same; although the present application has been described in detail with reference to the foregoing embodiments, it should be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; such modifications and substitutions do not substantially depart from the spirit and scope of the embodiments of the present application and are intended to be included within the scope of the present application.
Claims (10)
1. A method for finely simulating a mountainous terrain wind speed field is characterized by comprising the following steps:
simplifying the mountain into a semi-ellipsoid structure which can be described in a parameterization way and establishing a three-dimensional calculation model;
establishing a cuboid calculation domain which is large enough according to the size of the three-dimensional calculation model of the mountain;
applying wind speed according with an exponential distribution rule to the entrance plane of the cuboid calculation domain through a turbulence model;
observing the spatial distribution condition of the wind speed field in the cuboid calculation domain, extracting the wind direction angles and the wind speeds at different coordinates, searching the relation between the wind speed field and the mountain terrain parameters, and fitting by using a mathematical formula.
2. The method for refining the mountainous terrain wind speed field according to claim 1, wherein the step of simplifying the mountains into the semi-ellipsoid structure capable of being described in a parameterization manner and establishing the three-dimensional calculation model specifically comprises the steps of:
converting the actual measured values of the real mountain area into parameters of mountain radius, mountain height, mountain distance and gradient for inputting;
according to the vegetation coverage degree of the mountain surface, the ground roughness is set to be 1.3-1.7 times of that of the flat ground.
3. The method for refining the mountainous terrain wind speed field according to claim 2, wherein the establishing of the cuboid calculation domain which is large enough according to the size of the three-dimensional calculation model of the mountain comprises:
setting the length of the cuboid calculation domain to be 8-12 times of the sum of the radius of the mountain and the distance between the mountains;
setting the width of the cuboid calculation domain to be 8-12 times of the radius of the mountain;
setting the height of the cuboid calculation domain to be 6-10 times of the height of the mountain;
setting the surfaces of the cuboid calculation domain except the speed inlet and the free outlet as standard wall functions without slippage;
and taking the part of the bottom surface of the cuboid calculation domain except the mountain area as a plain, dividing the plain into four types of landforms according to different actual environments, wherein each type of landform has a corresponding ground roughness length, and converting the numerical value of the ground roughness length multiplied by 20 times into a ground roughness height parameter to be input into finite element simulation software.
4. The method for the refined simulation of the mountainous terrain wind speed field according to claim 3, wherein the establishing of the cuboid calculation domain which is large enough according to the size of the three-dimensional calculation model of the mountain further comprises the step of carrying out local encryption on a grid at the junction of the cuboid calculation domain and the three-dimensional calculation model of the mountain, so that the grid length is 1-2 meters.
5. The method for the refined simulation of the mountainous terrain wind speed field according to claim 3, wherein the roughness length of the ground is 0.01m, 0.05m, 0.3m and 1.0m corresponding to four types of landforms.
6. The method for finely simulating the mountainous terrain wind speed field according to claim 1, wherein when the wind speed conforming to the exponential distribution rule is applied to the entrance plane of the cuboid calculation domain through the turbulence model, the turbulence model selects a Rearizable k-epsilon model, and takes the average wind speed at the height of 10m as the basic wind speed, so that the relation between the speed and the height meets the Davenport exponential wind formula and the wind speed vertically enters the entrance plane in the form of a custom function, and the expression is as follows:
in the formula (I), the compound is shown in the specification,
is the average wind speed and is the average wind speed,
the basic wind speed is adopted, y is the coordinate height, and alpha is the ground roughness coefficient;
the turbulence kinetic energy and the turbulence dissipation ratio of the incident wind speed are set in the form of a custom function, and the expression is as follows:
where k (y) denotes the kinetic energy of turbulence, V (y) denotes the velocity at height y, I (y) denotes the turbulence at height y, ε is the dissipation ratio of turbulence, L u (y) is the integral scale of turbulence, C u The value is 0.09, and K is 0.42; m is rice, y b Critical height of the segment, y, for turbulence g Is the gradient wind height.
7. The method for the refined simulation of the mountainous terrain wind speed field of claim 6, wherein the basic wind speed is 25m/s-35 m/s.
8. The method for refining simulation of the mountainous terrain wind speed field according to claim 6, wherein the ground roughness coefficient α and the gradient wind height y are g And a piecewise critical height y of turbulence b Corresponding values of (a) correspond to four types of landforms and are respectively taken as follows:
the ground roughness coefficient alpha corresponding to the landform type A is 0.12, and the gradient wind height y g 300m, a piecewise critical height of turbulence y b Is 5 m;
the ground roughness coefficient alpha corresponding to the landform type B is 0.16, and the gradient wind height y g A critical height y of 350m, segment of turbulence b Is 5 m;
the ground roughness coefficient alpha corresponding to the landform type C is 0.22, and the gradient wind height y g A segment critical height y of 400m, turbulence b Is 5 m;
the ground roughness coefficient alpha corresponding to the landform type D is 0.30, and the gradient wind height y g 450m, a piecewise critical height of turbulence y b Is 10 m.
9. The method for finely simulating the mountainous terrain wind speed field according to claim 1, wherein the step of observing the cuboid to calculate the spatial distribution of the wind speed field in the region, extracting the wind direction angles and the wind speed at different coordinates, searching the relation between the wind speed field and the mountainous terrain parameters, and fitting by using a mathematical formula comprises:
extracting the speed and gradient of corresponding points, lines and surfaces according to the specific three-dimensional coordinates of the mountain positions of the infrastructure facilities;
and (3) sorting the extracted corresponding points, lines and planes of speed and gradient and the parameters corresponding to the three-dimensional calculation model of the mountain, carrying out nonlinear fitting by taking an exponential form with the base number of e as a frame, and carrying out convergence verification from the mathematical angle.
10. A mountain area topography wind speed field's simulation system that refines, characterized by includes:
the model building module is used for simplifying the mountain into a semi-ellipsoid structure which can be described in a parameterization way and building a three-dimensional calculation model;
the cuboid calculation domain establishing module is used for establishing a cuboid calculation domain which is large enough according to the size of the three-dimensional calculation model of the mountain;
the wind speed applying module is used for applying wind speed which accords with an exponential distribution rule to the entrance plane of the cuboid calculation domain through the turbulence model;
and the connection fitting module is used for observing the spatial distribution condition of the wind speed field in the cuboid calculation domain, extracting the wind direction angles and the wind speed at different coordinates, searching the connection between the wind speed field and the topographic parameters of the mountainous area, and fitting by using a mathematical formula.
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