CN116415527B - Urban block wind environment assessment method and system - Google Patents

Abstract

The invention discloses a city block wind environment assessment method and a system, wherein the method comprises the following steps: determining target months and all target wind directions which meet preset natural ventilation conditions according to meteorological observation data; calculating wind environment influence indexes; wherein, wind environment influence index includes: the open space rate, the number of buildings in unit area, the ratio of the width of the air inlet to the width of the windward side, the wind guide length in unit area and the wind resistance area in unit area; according to the wind environment influence index and a linear regression equation based on the wind environment influence index and the wind speed ratio, calculating the wind speed ratio of each target wind direction; according to the occurrence frequency of each target wind direction in the target month, carrying out weighted summation on all wind speed ratios to obtain a wind environment comprehensive score; and evaluating the wind environment of the target area according to the wind environment comprehensive score to obtain a wind environment evaluation result. The method can simplify the calculation process of wind environment assessment, save time and labor cost and improve the calculation efficiency of urban block wind environment assessment.

Description

A method and system for assessing wind environment in urban neighborhoods

Technical field

The invention relates to the technical field of urban planning, and in particular to a method and system for assessing wind environment in urban blocks.

Background technique

For the wind environment assessment of small-scale urban block planning and design plans, technical methods such as computational fluid dynamics numerical simulation and wind tunnel experiments are currently used at home and abroad to estimate wind environment-related indicators such as wind speed ratio, wind speed, and temperature, and use this to evaluate the city. The wind environment of the neighborhood. However, wind speed ratio, wind speed, temperature, etc. are all effect indicators, which must be obtained through field monitoring, wind tunnel experiments, CFD simulations or complex iterative operations. The simulation and experimental processes require a lot of time and labor costs, and the workload is huge. As a result, the computational efficiency of wind environment assessment in urban blocks is low.

Contents of the invention

The invention provides an urban block wind environment assessment method and system, which can simplify the calculation process of wind environment assessment, save time and labor costs, and improve the calculation efficiency of urban block wind environment assessment.

Embodiments of the present invention provide a method for assessing wind environment in urban blocks, including:

Obtain meteorological observation data of the target area, and determine the target month that meets the preset natural ventilation conditions based on the meteorological observation data, and all target wind directions in the target month;

Calculate wind environment impact indicators; wherein, the wind environment impact indicators include: the open space rate of the target area, the number of buildings per unit area of the target area, the width of the air inlet and the windward surface corresponding to each target wind direction The ratio of the width, the wind guide length per unit area corresponding to each target wind direction, and the wind blocking area per unit area corresponding to each target wind direction;

Calculate the wind speed ratio for each target wind direction according to the wind environment impact index and the preset wind speed ratio calculation equation; wherein the wind speed ratio calculation equation is a linear regression equation based on the wind environment impact index and the wind speed ratio;

According to the frequency of occurrence of each target wind direction in the target month, perform a weighted sum of all the wind speed ratios to obtain a comprehensive wind environment score;

According to the comprehensive wind environment score, the wind environment of the target area is evaluated to obtain a wind environment assessment result.

As an improvement to the above solution, the meteorological observation data includes the monthly average temperature of each month, the monthly average absolute humidity of each month, and the wind direction frequency of each wind direction;

Then, the preset natural ventilation conditions include:

The monthly average temperature is greater than the preset temperature threshold, and the monthly average absolute humidity is greater than the preset humidity threshold;

The wind direction frequency is greater than the preset frequency threshold.

As an improvement to the above solution, the wind speed ratio calculation equation is specifically:

Among them, a ₁ is a preset constant term, a ₂ is the first correlation coefficient corresponding to the wind guide length per unit area, a ₃ is the second correlation coefficient corresponding to the ratio of the width of the air inlet and the width of the windward surface, and a ₄ is the second correlation coefficient corresponding to the wind length per unit area. The third correlation coefficient corresponding to the wind resistance area, a ₅ is the fourth correlation coefficient corresponding to the open space rate, a ₆ is the fifth correlation coefficient corresponding to the number of buildings per unit area, R _hgi is the wind speed ratio of the i-th target wind direction, R _di is the wind guide length per unit area corresponding to the i-th target wind direction, R _ri is the ratio of the width of the air inlet corresponding to the i-th target wind direction and the width of the windward surface, and R _zi is the upper resistance per unit area corresponding to the i-th target wind direction. Wind area, R _k is the open space ratio of the target area, and R _j is the number of buildings per unit area in the target area.

As an improvement to the above solution, all the wind speed ratios are weighted and summed according to the frequency of occurrence of each target wind direction in the target month to obtain a comprehensive wind environment score, specifically as follows:

A comprehensive wind environment score is obtained by weighting the sum of all the wind speed ratios according to the following formula:

Among them, R is the comprehensive score of the wind environment, P _i is the occurrence frequency of the i-th target wind direction in the target month, R _hgi is the wind speed ratio of the i-th target wind direction, and n is the frequency of the i-th target wind direction in the target month. The total number of target wind directions.

As an improvement to the above solution, the open space rate of the target area is calculated by the following formula:

Wherein, R _k is the open space ratio of the target area, S is the minimum convex area of the target area, and S _kc is the open space area within the minimum convex area of the target area.

As an improvement to the above solution, the number of buildings per unit area in the target area is calculated by the following formula:

Among them, R _j is the number of buildings per unit area in the target area, N _j is the number of buildings in the target area, and S is the minimum convex area of the target area.

As an improvement to the above solution, the wind guide length per unit area corresponding to each target wind direction is calculated by the following formula:

Among them, R _di is the wind guide length per unit area corresponding to the i-th target wind direction, L _j is the length of the windward surface of the j-th building within the minimum convex polygon of the target area, and α _ji is the minimum convexity of the target area. The wind direction angle between the j-th building within the polygon and the i-th target wind direction, S is the minimum convex polygon area of the target area.

As an improvement to the above solution, the wind blocking area per unit area corresponding to each target wind direction is calculated by the following formula:

Among them, R _zi is the wind resistance area per unit area corresponding to the i-th target wind direction, S _j is the windward surface area of the j-th building within the minimum convex shape of the target area, and α _ji is the minimum area of the target area. The wind direction angle between the j-th building within the convex shape and the i-th target wind direction, S is the minimum convex shape area of the target area.

As an improvement to the above solution, the wind environment of the target area is evaluated based on the comprehensive wind environment score, and the wind environment assessment results are obtained, including:

When the comprehensive wind environment score is greater than the first preset value, the wind environment assessment result is determined to be excellent wind environment;

When the comprehensive score of the wind environment is greater than the second preset value and less than or equal to the first preset value, it is determined that the wind environment assessment result is a good wind environment;

When the comprehensive wind environment score is greater than the third preset value and less than or equal to the second preset value, the wind environment assessment result is determined to be moderate wind environment;

When the comprehensive wind environment score is greater than the fourth preset value and less than or equal to the third preset value, it is determined that the wind environment assessment result is poor wind environment;

When the comprehensive wind environment score is less than or equal to the fourth preset value, the wind environment assessment result is determined to be a poor wind environment; wherein the first preset value is greater than the second preset value, so The second preset value is greater than the third preset value, and the third preset value is greater than the fourth preset value.

Correspondingly, another embodiment of the present invention provides an urban block wind environment assessment system, including:

The wind environment base analysis module is used to obtain meteorological observation data of the target area, and determine the target month that meets the preset natural ventilation conditions based on the meteorological observation data, as well as all target wind directions in the target month;

The wind environment impact index calculation module is used to calculate the wind environment impact index; wherein the wind environment impact index includes: the open space rate of the target area, the number of buildings per unit area of the target area, the number of buildings per unit area of the target area, The ratio of the width of the air inlet corresponding to the wind direction and the width of the windward surface, the wind guide length per unit area corresponding to each target wind direction, and the wind blocking area per unit area corresponding to each target wind direction;

The wind direction and wind speed ratio calculation module is used to calculate the wind speed ratio of each target wind direction according to the wind environment impact index and the preset wind speed ratio calculation equation; wherein the wind speed ratio calculation equation is based on the wind environment impact index and the preset wind speed ratio calculation equation. Linear regression equation of wind speed ratio;

The wind environment comprehensive scoring module is used to perform a weighted sum of all the wind speed ratios according to the frequency of occurrence of each target wind direction in the target month to obtain a comprehensive wind environment score;

A comprehensive wind environment assessment module is used to assess the wind environment of the target area based on the comprehensive wind environment score and obtain wind environment assessment results.

Compared with the existing technology, the urban block wind environment assessment method and system disclosed in the embodiments of the present invention first obtain meteorological observation data of the target area, determine the target month that satisfies the preset natural ventilation conditions based on the meteorological observation data, and All target wind directions in the target month; calculate wind environment impact indicators; wherein, the wind environment impact indicators include: the open space rate of the target area, the number of buildings per unit area in the target area, and the number of buildings per unit area in the target area. The ratio of the width of the air inlet corresponding to the target wind direction and the width of the windward surface, the wind guide length per unit area corresponding to each target wind direction, and the wind blocking area per unit area corresponding to each target wind direction; according to the wind environment impact index and the preset wind speed ratio calculation equation to calculate the wind speed ratio for each target wind direction; wherein, the wind speed ratio calculation equation is a linear regression equation based on the wind environment impact index and the wind speed ratio; according to each target wind direction, Based on the occurrence frequency of the target month, all the wind speed ratios are weighted and summed to obtain a comprehensive wind environment score; based on the comprehensive wind environment score, the wind environment of the target area is evaluated to obtain a wind environment assessment result. Therefore, it is only necessary to use the existing index parameters in the planning and design scheme of the urban target area to calculate the corresponding wind environment impact index, and then calculate the wind speed ratio of each target wind direction to conduct wind environment assessment of the target area. The calculation process It is simple, can save time and labor costs to a certain extent, and improve the calculation efficiency of wind environment assessment in urban blocks.

Description of the drawings

Figure 1 is a schematic flowchart of an urban block wind environment assessment method provided by an embodiment of the present invention.

Figure 2 is a schematic diagram of a minimum convex edge delimitation provided by an embodiment of the present invention.

Figure 3 is a schematic diagram for calculating the ratio of the width of the air inlet and the width of the windward surface provided by an embodiment of the present invention.

Figure 4 is a schematic diagram of the wind direction angle of a building provided by an embodiment of the present invention.

Figure 5 is a schematic structural diagram of an urban block wind environment assessment system provided by an embodiment of the present invention.

Detailed ways

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only some of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative efforts fall within the scope of protection of the present invention.

Referring to Figure 1, Figure 1 is a schematic flow chart of a wind environment assessment method for urban blocks provided by an embodiment of the present invention.

The urban block wind environment assessment method provided by the embodiment of the present invention includes the steps:

S11. Obtain the meteorological observation data of the target area, and determine the target month that meets the preset natural ventilation conditions and all target wind directions in the target month based on the meteorological observation data;

S12. Calculate wind environment impact indicators; wherein, the wind environment impact indicators include: the open space rate of the target area, the number of buildings per unit area of the target area, the width of the air inlet corresponding to each target wind direction, and The ratio of the width of the windward surface, the wind guide length per unit area corresponding to each target wind direction, and the wind blocking area per unit area corresponding to each target wind direction;

S13. Calculate the wind speed ratio for each target wind direction according to the wind environment impact index and the preset wind speed ratio calculation equation; wherein the wind speed ratio calculation equation is a linear regression equation based on the wind environment impact index and the wind speed ratio. ;

S14. According to the frequency of occurrence of each target wind direction in the target month, perform a weighted sum of all the wind speed ratios to obtain a comprehensive wind environment score;

S15. Evaluate the wind environment of the target area according to the comprehensive score of the wind environment, and obtain the wind environment assessment result.

Optionally, the meteorological observation data includes the monthly average temperature of each month, the monthly average absolute humidity of each month, and the wind direction frequency of each wind direction;

Then, the preset natural ventilation conditions include:

The monthly average temperature is greater than the preset temperature threshold, and the monthly average absolute humidity is greater than the preset humidity threshold;

The wind direction frequency is greater than the preset frequency threshold.

Specifically, the meteorological observation data is typical year-by-hour meteorological data.

Optionally, the preset temperature threshold is 26°C, the preset humidity threshold is 15g/m ³ , and the preset frequency threshold is 5%.

For example, taking the preset temperature threshold as 26°C, the preset humidity threshold as 15g/m ³ , and the preset frequency threshold as 5%, in actual operation, the preset temperature threshold can be determined according to the planning and design scheme. Typical annual hourly meteorological data of the target area are used to select months with an average monthly temperature greater than 26°C and an average monthly absolute humidity greater than 15g/m3 as the target months, and wind directions with a wind direction frequency greater than 5% in the target month as the target wind direction.

It should be noted that the preset temperature threshold, the preset humidity threshold, and the preset frequency threshold can be adjusted according to actual conditions, and their specific values are not limited here.

As one specific embodiment, the wind speed ratio calculation equation is specifically:

Among them, a ₁ is a preset constant term, a ₂ is the first correlation coefficient corresponding to the wind guide length per unit area, a ₃ is the second correlation coefficient corresponding to the ratio of the width of the air inlet and the width of the windward surface, and a ₄ is the second correlation coefficient corresponding to the wind length per unit area. The third correlation coefficient corresponding to the wind resistance area, a ₅ is the fourth correlation coefficient corresponding to the open space rate, a ₆ is the fifth correlation coefficient corresponding to the number of buildings per unit area, R _hgi is the wind speed ratio of the i-th target wind direction, R _di is the wind guide length per unit area corresponding to the i-th target wind direction, R _ri is the ratio of the width of the air inlet corresponding to the i-th target wind direction and the width of the windward surface, and R _zi is the upper resistance per unit area corresponding to the i-th target wind direction. Wind area, R _k is the open space ratio of the target area, and R _j is the number of buildings per unit area in the target area.

It should be noted that the value of a ₆ is a negative number.

Alternatively, a ₁ =0.117, a ₂ =9.763, a ₃ =0.556, a ₄ =0.013, a ₅ =0.26, a ₆ =-0.03.

It is worth noting that the wind speed ratio calculation equation is constructed based on linear regression analysis of wind environment impact indicators and corresponding wind speed ratios from experimental simulations or historical measurements. It is a linear regression equation based on wind environment impact indicators and wind speed ratio. The specific values of a ₁ , a ₂ , a ₃ , a ₄ , a ₅ , and a ₆ can be adjusted according to actual correlation analysis. For example, 270 urban block models are constructed, CFD and GIS technologies are used to simulate the wind environment of urban blocks, and wind environment impact indicators and wind speed ratios are calculated. Taking the wind speed ratio within the minimum convex shape as the dependent variable and the wind environment impact index as the independent variable, a multiple linear regression analysis was performed to obtain the wind speed ratio calculation equation, that is, Of course, in actual operation, the wind speed ratio calculation equation can also be other mathematical equations or models that predict the wind speed ratio by analyzing the correlation between multiple indicators in the wind environment impact indicators and the wind speed ratio.

Specifically, based on the frequency of occurrence of each target wind direction in the target month, a weighted summation of all the wind speed ratios is performed to obtain a comprehensive wind environment score, specifically as follows:

A comprehensive wind environment score is obtained by weighting the sum of all the wind speed ratios according to the following formula:

Among them, R is the comprehensive score of the wind environment, P _i is the occurrence frequency of the i-th target wind direction in the target month, R _hgi is the wind speed ratio of the i-th target wind direction, and n is the frequency of the i-th target wind direction in the target month. The total number of target wind directions.

Specifically, before calculating the wind environment impact index, the method further includes: delimiting a minimum convex polygon of the target area. Referring to Figure 2, specifically, the outermost points of all buildings in the target area are connected, and the parts exceeding the planning boundary of the target area are removed to obtain the minimum convex shape of the target area. It should be noted that the purpose of defining the minimum convex shape of the target area is to avoid differences in wind speed ratios caused by the same building layout and different evaluation ranges.

In some preferred embodiments, the open space ratio of the target area is calculated by the following formula:

Wherein, R _k is the open space ratio of the target area, S is the minimum convex area of the target area, and S _kc is the open space area within the minimum convex area of the target area.

Understandably, wind mainly flows in the open space of urban blocks. Therefore, the amount of open space is the basis for evaluating the quality of wind environment in urban blocks. Generally speaking, the higher the open space ratio of an urban block, the better its wind environment. The open space ratio is equal to the ratio of the area of open space within the smallest convex shape to the area of the smallest convex shape in the city block.

In some preferred embodiments, the number of buildings per unit area in the target area is calculated by the following formula:

Among them, R _j is the number of buildings per unit area in the target area, N _j is the number of buildings in the target area, and S is the minimum convex area of the target area.

It is worth mentioning that the more continuous the open space is, the larger the space will be and the better the wind environment will be. When the open space area is constant, the more buildings there are per unit area in the target area, the smaller the independent open space area will be, and the open space will be more fragmented by the buildings, and the wind flow in it will encounter The more friction surfaces there are, the wind speed will also be reduced to a greater extent. On the contrary, the smaller the number of buildings per unit area in the target area, the larger the independent open space area, and the wind will encounter fewer friction surfaces when flowing therein, and the wind speed can be maintained.

In some preferred embodiments, the ratio of the width of the air inlet corresponding to each target wind direction and the width of the windward surface is calculated by the following formula:

Among them, R _ri is the ratio of the width of the air inlet corresponding to the i-th target wind direction and the width of the windward surface, L _r is the width of the air inlet corresponding to the i-th target wind direction, and L _y is the width of the windward surface corresponding to the i-th target wind direction.

Understandably, the ratio of the width of the air inlet to the width of the windward surface can reflect the ability of wind to blow into urban blocks. Referring to Figure 3, the width of the windward surface is the projected length of the smallest convex shape perpendicular to the wind direction, and the width of the air inlet is the projected length of the common edge of the unobstructed surface and the smallest convex shape perpendicular to the wind direction.

Referring to Figure 4, the wind direction angle is the angle between the wind direction and the normal line of the building's exterior wall. In actual practice, if the wind blows directly into the building, the wind direction angle is 0°. The closer the wind direction angle is to 45°, the greater the wind speed. Spectral analysis shows that the closer the wind direction angle is to 45°, the better the building is able to direct wind into the open space within the target area. When the wind direction angle exceeds 45°, it is affected by shock waves. On the contrary, the windward side cannot fully guide the wind into urban blocks. It should be noted that the difference between the wind direction angles changes linearly, but the change amplitude of the wind speed ratio is not linear, but shows a parabolic change trend. Therefore, it can be considered that the closer the wind direction angle is to 45°, the better the wind guide performance of the surface will be. If the wind direction angle is less than or greater than 45°, the wind guide performance of the surface will decrease. Based on this, the present invention assumes that the wind guide length of a windward surface is equal to the product of the sine value of twice the wind direction angle of the surface and the length of the surface, that is, L _d = Lsin2α; where, L _d is the wind guide length of the windward surface, and L is The length of the windward surface, α is the wind direction angle.

In some preferred embodiments, the wind guide length per unit area corresponding to each target wind direction is calculated by the following formula:

Among them, R _di is the wind guide length per unit area corresponding to the i-th target wind direction, L _j is the length of the windward surface of the j-th building within the minimum convex polygon of the target area, and α _ji is the minimum convexity of the target area. The wind direction angle between the j-th building within the polygon and the i-th target wind direction, S is the minimum convex polygon area of the target area.

Understandably, the larger the wind guide length per unit area is, the better the wind guide performance of the building layout is, and the better it can guide wind into the urban blocks. The wind guide length per unit area is equal to the ratio of the sum of the wind guide lengths of all windward surfaces in the target area to the area of the smallest convex edge.

In some preferred embodiments, the wind blocking area per unit area corresponding to each target wind direction is calculated by the following formula:

Among them, R _zi is the wind resistance area per unit area corresponding to the i-th target wind direction, S _j is the windward surface area of the j-th building within the minimum convex shape of the target area, and α _ji is the minimum area of the target area. The wind direction angle between the j-th building within the convex shape and the i-th target wind direction, S is the minimum convex shape area of the target area.

It should be noted that the degree of wind blocking of a building mainly depends on the size of the wind blocking area. The larger the wind blocking area, the stronger the wind blocking effect of the building. The wind resistance area of a building is the projected area of the windward surface of the building perpendicular to the wind direction, which is numerically equal to the area of the windward surface multiplied by the cosine of the wind direction angle of the windward surface. The wind blocking area per unit area can be used to evaluate the degree of wind blocking of a building. Its value is equal to the ratio of the sum of the projected areas of the windward surfaces perpendicular to the wind direction of all buildings in the target area to the area of the smallest convex edge.

It is worth noting that in the embodiment of the present invention, the parameters for calculating the wind environment impact index can be obtained through the planning and design scheme of the target area. Therefore, it is only necessary to use the existing index parameters in the planning and design scheme of the target area. , the wind environment impact index can be calculated, and then the wind speed ratio of each target wind direction is calculated through the wind environment impact index and the preset wind speed ratio calculation equation, and the wind environment assessment result is obtained based on the wind speed ratio of all target wind directions. There is no need to conduct experiments, simulations or iterative calculations on the wind environment of the target area like existing technologies. The calculation process is simple, efficient and easy to operate, and the wind environment assessment results are relatively stable and reliable. Therefore, the present invention is suitable for wind environment assessment of urban block planning and design schemes, and is easy to be promoted in practice.

In an optional implementation, the wind environment of the target area is evaluated based on the comprehensive wind environment score, and the wind environment assessment results are obtained, including:

When the comprehensive wind environment score is greater than the first preset value, the wind environment assessment result is determined to be excellent wind environment;

When the comprehensive score of the wind environment is greater than the second preset value and less than or equal to the first preset value, it is determined that the wind environment assessment result is a good wind environment;

When the comprehensive wind environment score is greater than the third preset value and less than or equal to the second preset value, the wind environment assessment result is determined to be moderate wind environment;

When the comprehensive wind environment score is greater than the fourth preset value and less than or equal to the third preset value, it is determined that the wind environment assessment result is poor wind environment;

When the comprehensive wind environment score is less than or equal to the fourth preset value, the wind environment assessment result is determined to be a poor wind environment; wherein the first preset value is greater than the second preset value, so The second preset value is greater than the third preset value, and the third preset value is greater than the fourth preset value.

Preferably, the first preset value is 0.8, the second preset value is 0.6, the third preset value is 0.4, and the fourth preset value is 0.2.

It can be understood that in this embodiment, the wind environment assessment results are divided into five levels: excellent, good, medium, poor, and poor according to the degree of wind environment; among them, excellent wind environment is better than good wind environment. , a good wind environment is better than a moderate wind environment, a moderate wind environment is better than a poor wind environment, and a poor wind environment is better than a poor wind environment. Of course, in actual operations, the wind environment assessment results can also be divided into first level, second level, third level, fourth level, and fifth level according to actual needs. The higher the level, the better/worse the wind environment. In addition, the wind environment assessment results can also be divided into four levels or three levels. There are no specific limitations on the determination and classification of the wind environment assessment results here.

Refer to Figure 5, which is a schematic structural diagram of an urban block wind environment assessment system provided by an embodiment of the present invention.

The urban block wind environment assessment system provided by the embodiment of the present invention includes:

The wind environment base analysis module 21 is used to obtain meteorological observation data of the target area, and determine the target month that meets the preset natural ventilation conditions based on the meteorological observation data, as well as all target wind directions in the target month;

The wind environment impact index calculation module 22 is used to calculate the wind environment impact index; wherein, the wind environment impact index includes: the open space rate of the target area, the number of buildings per unit area of the target area, each of the The ratio of the width of the air inlet corresponding to the target wind direction and the width of the windward surface, the wind guide length per unit area corresponding to each target wind direction, and the wind blocking area per unit area corresponding to each target wind direction;

The wind direction and wind speed ratio calculation module 23 is used to calculate the wind speed ratio of each target wind direction according to the wind environment impact index and the preset wind speed ratio calculation equation; wherein the wind speed ratio calculation equation is based on the wind environment impact index. Linear regression equation with wind speed ratio;

The wind environment comprehensive scoring module 24 is used to perform a weighted sum of all the wind speed ratios according to the frequency of occurrence of each target wind direction in the target month to obtain a comprehensive wind environment score;

The comprehensive wind environment assessment module 25 is used to assess the wind environment of the target area based on the comprehensive wind environment score and obtain a wind environment assessment result.

Optionally, the meteorological observation data in the wind environment base analysis module 21 includes the monthly average temperature of each month, the monthly average absolute humidity of each month, and the wind direction frequency of each wind direction;

Then, the preset natural ventilation conditions include:

The monthly average temperature is greater than the preset temperature threshold, and the monthly average absolute humidity is greater than the preset humidity threshold;

The wind direction frequency is greater than the preset frequency threshold.

As one specific embodiment, the wind speed ratio calculation equation in the wind direction and wind speed ratio calculation module 23 is specifically:

Among them, a ₁ is a preset constant term, a ₂ is the first correlation coefficient corresponding to the wind guide length per unit area, a ₃ is the second correlation coefficient corresponding to the ratio of the width of the air inlet and the width of the windward surface, and a ₄ is the second correlation coefficient corresponding to the wind length per unit area. The third correlation coefficient corresponding to the wind resistance area, a ₅ is the fourth correlation coefficient corresponding to the open space rate, a ₆ is the fifth correlation coefficient corresponding to the number of buildings per unit area, R _hgi is the wind speed ratio of the i-th target wind direction, R _di is the wind guide length per unit area corresponding to the i-th target wind direction, R _ri is the ratio of the width of the air inlet corresponding to the i-th target wind direction and the width of the windward surface, and R _zi is the upper resistance per unit area corresponding to the i-th target wind direction. Wind area, R _k is the open space ratio of the target area, and R _j is the number of buildings per unit area in the target area.

Specifically, the comprehensive wind environment scoring module 24 is used for:

A comprehensive wind environment score is obtained by weighting the sum of all the wind speed ratios according to the following formula:

Among them, R is the comprehensive score of the wind environment, P _i is the occurrence frequency of the i-th target wind direction in the target month, R _hgi is the wind speed ratio of the i-th target wind direction, and n is the frequency of the i-th target wind direction in the target month. The total number of target wind directions.

In some preferred embodiments, the wind environment impact index calculation module 22 calculates the open space rate of the target area through the following formula:

Wherein, R _k is the open space ratio of the target area, S is the minimum convex area of the target area, and S _kc is the open space area within the minimum convex area of the target area.

In some preferred embodiments, the wind environment impact index calculation module 22 calculates the number of buildings per unit area in the target area through the following formula:

Among them, R _j is the number of buildings per unit area in the target area, N _j is the number of buildings in the target area, and S is the minimum convex area of the target area.

In some preferred embodiments, the wind environment impact index calculation module 22 calculates the ratio of the air inlet width and the windward surface width corresponding to each target wind direction through the following formula:

Among them, R _ri is the ratio of the width of the air inlet corresponding to the i-th target wind direction and the width of the windward surface, L _r is the width of the air inlet corresponding to the i-th target wind direction, and L _y is the width of the windward surface corresponding to the i-th target wind direction.

In some preferred embodiments, the wind environment impact index calculation module 22 calculates the wind guide length per unit area corresponding to each target wind direction through the following formula:

Among them, R _di is the wind guide length per unit area corresponding to the i-th target wind direction, L _j is the length of the windward surface of the j-th building within the minimum convex polygon of the target area, and α _ji is the minimum convexity of the target area. The wind direction angle between the j-th building within the polygon and the i-th target wind direction, S is the minimum convex polygon area of the target area.

In some preferred embodiments, the wind environment impact index calculation module 22 calculates the wind blocking area per unit area corresponding to each target wind direction through the following formula:

Among them, R _zi is the wind resistance area per unit area corresponding to the i-th target wind direction, S _j is the windward surface area of the j-th building within the minimum convex shape of the target area, and α _ji is the minimum area of the target area. The wind direction angle between the j-th building within the convex shape and the i-th target wind direction, S is the minimum convex shape area of the target area.

In an optional implementation, the wind environment comprehensive assessment module 25 is specifically used for:

When the comprehensive wind environment score is greater than the first preset value, the wind environment assessment result is determined to be excellent wind environment;

When the comprehensive score of the wind environment is greater than the second preset value and less than or equal to the first preset value, it is determined that the wind environment assessment result is a good wind environment;

When the comprehensive wind environment score is greater than the third preset value and less than or equal to the second preset value, the wind environment assessment result is determined to be moderate wind environment;

When the comprehensive wind environment score is greater than the fourth preset value and less than or equal to the third preset value, it is determined that the wind environment assessment result is poor wind environment;

When the comprehensive wind environment score is less than or equal to the fourth preset value, the wind environment assessment result is determined to be a poor wind environment; wherein the first preset value is greater than the second preset value, so The second preset value is greater than the third preset value, and the third preset value is greater than the fourth preset value.

It should be noted that the relevant detailed descriptions and beneficial effects of each embodiment of the urban block wind environment assessment device of this embodiment can be referred to the relevant detailed descriptions and beneficial effects of each embodiment of the above-mentioned urban block wind environment assessment method. Herein No longer.

It should be noted that the device embodiments described above are only illustrative. The units described as separate components may or may not be physically separated. The components shown as units may or may not be physically separate. The unit can be located in one place, or it can be distributed across multiple network units. Some or all of the modules can be selected according to actual needs to achieve the purpose of the solution of this embodiment. In addition, in the drawings of the device embodiments provided by the present invention, the connection relationship between modules indicates that there are communication connections between them, which can be specifically implemented as one or more communication buses or signal lines. Persons of ordinary skill in the art can understand and implement the method without any creative effort.

In summary, the embodiments of the present invention provide an urban block wind environment assessment method and system. First, the meteorological observation data of the target area is obtained, and the target month that satisfies the preset natural ventilation conditions is determined based on the meteorological observation data, and the All target wind directions in the target month; calculate wind environment impact indicators; wherein, the wind environment impact indicators include: the open space rate of the target area, the number of buildings per unit area in the target area, the number of buildings per unit area in the target area, The ratio of the width of the air inlet corresponding to the wind direction and the width of the windward surface, the wind guide length per unit area corresponding to each target wind direction, and the wind blocking area per unit area corresponding to each target wind direction; according to the wind environment impact index and The preset wind speed ratio calculation equation is used to calculate the wind speed ratio of each target wind direction; wherein, the wind speed ratio calculation equation is a linear regression equation based on the wind environment impact index and the wind speed ratio; according to the location of each target wind direction, Based on the occurrence frequency of the target month, a weighted sum of all the wind speed ratios is performed to obtain a comprehensive wind environment score; based on the comprehensive wind environment score, the wind environment of the target area is evaluated to obtain a wind environment assessment result. Therefore, it is only necessary to use the existing index parameters in the planning and design scheme of the urban target area to calculate the corresponding wind environment impact index, and then calculate the wind speed ratio of each target wind direction to conduct wind environment assessment of the target area. The calculation process It is simple, can save time and labor costs to a certain extent, and improve the calculation efficiency of wind environment assessment in urban blocks.

The above is the preferred embodiment of the present invention. It should be noted that for those of ordinary skill in the art, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications are also regarded as It is the protection scope of the present invention.

Claims (5)

1. A method for assessing wind environment in urban blocks, which is characterized by including: Obtain meteorological observation data of the target area, and determine the target month that meets the preset natural ventilation conditions based on the meteorological observation data, and all target wind directions in the target month; Calculate wind environment impact indicators; wherein, the wind environment impact indicators include: the open space rate of the target area, the number of buildings per unit area of the target area, the width of the air inlet and the windward surface corresponding to each target wind direction The ratio of the width, the wind guide length per unit area corresponding to each target wind direction, and the wind blocking area per unit area corresponding to each target wind direction; Calculate the wind speed ratio for each target wind direction according to the wind environment impact index and the preset wind speed ratio calculation equation; wherein the wind speed ratio calculation equation is a linear regression equation based on the wind environment impact index and the wind speed ratio; According to the frequency of occurrence of each target wind direction in the target month, perform a weighted sum of all the wind speed ratios to obtain a comprehensive wind environment score; Evaluate the wind environment of the target area according to the comprehensive wind environment score, and obtain the wind environment assessment result; The open space rate of the target area is calculated by the following formula: Wherein, R _k is the open space ratio of the target area, S is the minimum convex edge area of the target area, and S _kc is the open space area within the minimum convex edge of the target area; The wind guide length per unit area corresponding to each target wind direction is calculated by the following formula: Among them, R _di is the wind guide length per unit area corresponding to the i-th target wind direction, L _j is the length of the windward surface of the j-th building within the minimum convex polygon of the target area, and α _ji is the minimum convexity of the target area. The wind direction angle between the j-th building within the polygon and the i-th target wind direction, S is the minimum convex polygon area of the target area; The wind blocking area per unit area corresponding to each target wind direction is calculated by the following formula: Among them, R _zi is the wind resistance area per unit area corresponding to the i-th target wind direction, S _j is the windward surface area of the j-th building within the minimum convex shape of the target area, and α _ji is the minimum area of the target area. The wind direction angle between the j-th building within the convex shape and the i-th target wind direction, S is the minimum convex shape area of the target area; The wind speed ratio calculation equation is specifically: Among them, a ₁ is a preset constant term, a ₂ is the first correlation coefficient corresponding to the wind guide length per unit area, a ₃ is the second correlation coefficient corresponding to the ratio of the width of the air inlet and the width of the windward surface, and a ₄ is the second correlation coefficient corresponding to the wind length per unit area. The third correlation coefficient corresponding to the wind resistance area, a ₅ is the fourth correlation coefficient corresponding to the open space rate, a ₆ is the fifth correlation coefficient corresponding to the number of buildings per unit area, R _hgi is the wind speed ratio of the i-th target wind direction, R _di is the wind guide length per unit area corresponding to the i-th target wind direction, R _ri is the ratio of the width of the air inlet corresponding to the i-th target wind direction and the width of the windward surface, and R _zi is the upper resistance per unit area corresponding to the i-th target wind direction. Wind area, R _k is the open space ratio of the target area, R _j is the number of buildings per unit area in the target area; According to the frequency of occurrence of each target wind direction in the target month, a weighted sum of all the wind speed ratios is performed to obtain a comprehensive wind environment score, specifically as follows: A comprehensive wind environment score is obtained by weighting the sum of all the wind speed ratios according to the following formula: Among them, R is the comprehensive score of the wind environment, P _i is the occurrence frequency of the i-th target wind direction in the target month, R _hgi is the wind speed ratio of the i-th target wind direction, and n is the frequency of the i-th target wind direction in the target month. The total number of target wind directions. 2. The urban block wind environment assessment method according to claim 1, wherein the meteorological observation data includes the monthly average temperature of each month, the monthly average absolute humidity of each month, and the wind direction frequency of each wind direction; The preset natural ventilation conditions include: The monthly average temperature is greater than the preset temperature threshold, and the monthly average absolute humidity is greater than the preset humidity threshold; The wind direction frequency is greater than the preset frequency threshold. 3. The urban block wind environment assessment method according to claim 1, characterized in that the number of buildings per unit area in the target area is calculated by the following formula: Among them, R _j is the number of buildings per unit area in the target area, N _j is the number of buildings in the target area, and S is the minimum convex area of the target area. 4. The urban block wind environment assessment method according to claim 1, wherein the wind environment of the target area is assessed according to the wind environment comprehensive score to obtain the wind environment assessment result, which includes: When the comprehensive wind environment score is greater than the first preset value, the wind environment assessment result is determined to be excellent wind environment; When the comprehensive score of the wind environment is greater than the second preset value and less than or equal to the first preset value, it is determined that the wind environment assessment result is a good wind environment; When the comprehensive wind environment score is greater than the third preset value and less than or equal to the second preset value, the wind environment assessment result is determined to be moderate wind environment; When the comprehensive wind environment score is greater than the fourth preset value and less than or equal to the third preset value, it is determined that the wind environment assessment result is poor wind environment; When the comprehensive wind environment score is less than or equal to the fourth preset value, the wind environment assessment result is determined to be a poor wind environment; wherein the first preset value is greater than the second preset value, so The second preset value is greater than the third preset value, and the third preset value is greater than the fourth preset value. 5. A wind environment assessment system for urban blocks, which is characterized by including: The wind environment base analysis module is used to obtain meteorological observation data of the target area, and determine the target month that meets the preset natural ventilation conditions based on the meteorological observation data, as well as all target wind directions in the target month; The wind environment impact index calculation module is used to calculate the wind environment impact index; wherein the wind environment impact index includes: the open space rate of the target area, the number of buildings per unit area of the target area, the number of buildings per unit area of the target area, The ratio of the width of the air inlet corresponding to the wind direction and the width of the windward surface, the wind guide length per unit area corresponding to each target wind direction, and the wind blocking area per unit area corresponding to each target wind direction; The wind direction and wind speed ratio calculation module is used to calculate the wind speed ratio of each target wind direction according to the wind environment impact index and the preset wind speed ratio calculation equation; wherein the wind speed ratio calculation equation is based on the wind environment impact index and the preset wind speed ratio calculation equation. Linear regression equation of wind speed ratio; The wind environment comprehensive scoring module is used to perform a weighted sum of all the wind speed ratios according to the frequency of occurrence of each target wind direction in the target month to obtain a comprehensive wind environment score; A comprehensive wind environment assessment module is used to assess the wind environment of the target area based on the comprehensive wind environment score and obtain wind environment assessment results; The open space rate of the target area is calculated by the following formula: Wherein, R _k is the open space ratio of the target area, S is the minimum convex edge area of the target area, and S _kc is the open space area within the minimum convex edge of the target area; The wind guide length per unit area corresponding to each target wind direction is calculated by the following formula: Among them, R _di is the wind guide length per unit area corresponding to the i-th target wind direction, L _j is the length of the windward surface of the j-th building within the minimum convex polygon of the target area, and α _ji is the minimum convexity of the target area. The wind direction angle between the j-th building within the polygon and the i-th target wind direction, S is the minimum convex polygon area of the target area; The wind blocking area per unit area corresponding to each target wind direction is calculated by the following formula: Among them, R _zi is the wind resistance area per unit area corresponding to the i-th target wind direction, S _j is the windward surface area of the j-th building within the minimum convex shape of the target area, and α _ji is the minimum area of the target area. The wind direction angle between the j-th building within the convex shape and the i-th target wind direction, S is the minimum convex shape area of the target area; The wind speed ratio calculation equation is specifically: Among them, a ₁ is a preset constant term, a ₂ is the first correlation coefficient corresponding to the wind guide length per unit area, a ₃ is the second correlation coefficient corresponding to the ratio of the width of the air inlet and the width of the windward surface, and a ₄ is the second correlation coefficient corresponding to the wind length per unit area. The third correlation coefficient corresponding to the wind resistance area, a ₅ is the fourth correlation coefficient corresponding to the open space rate, a ₆ is the fifth correlation coefficient corresponding to the number of buildings per unit area, R _hgi is the wind speed ratio of the i-th target wind direction, R _di is the wind guide length per unit area corresponding to the i-th target wind direction, R _ri is the ratio of the width of the air inlet corresponding to the i-th target wind direction and the width of the windward surface, and R _zi is the upper resistance per unit area corresponding to the i-th target wind direction. Wind area, R _k is the open space ratio of the target area, R _j is the number of buildings per unit area in the target area; According to the frequency of occurrence of each target wind direction in the target month, a weighted sum of all the wind speed ratios is performed to obtain a comprehensive wind environment score, specifically as follows: A comprehensive wind environment score is obtained by weighting the sum of all the wind speed ratios according to the following formula: Among them, R is the comprehensive score of the wind environment, P _i is the occurrence frequency of the i-th target wind direction in the target month, R _hgi is the wind speed ratio of the i-th target wind direction, and n is the frequency of the i-th target wind direction in the target month. The total number of target wind directions.