JP2013186714A - Wind environmental measure examination method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a wind environmental measure examination method for quickly determining valid building wind measures.SOLUTION: A wind environmental measure examination method 1 includes: modeling a space around a building; setting improvement object points around the building; generating a planar map around the building; setting a wind measure examination area in which a shielding object can be arranged on the planar map; searching the path of wind reaching the improvement object points when wind blows from a predetermined wind direction to the building as a backflow line; extracting an influence range in which the backflow line passes the height of the shielding object in the wind measure examination area; calculating an influence value at the improvement object point in each of the unit areas of the extracted influence range; repeatedly executing the above mentioned procedures about all the wind directions and all the improvement object points; calculating an influence cumulative value by cumulatively adding the applied influence values about each unit area of the wind measure examination area; and displaying the scale of the influence cumulative value in each unit area of the wind measure examination area on the planar map.

Description

  The present invention relates to a wind environment countermeasure examination method.

  Conventionally, as a measure against building wind, a shield such as windproof planting and windbreaks has been arranged around the building. Here, the building wind means strong winds such as downwinds, valley winds, and street winds that occur in a narrow area around the building.

The arrangement of windbreak planting and windbreak fences is determined, for example, by the following procedure.
The first method is a method of performing numerical analysis (see Patent Document 1). That is, windproof planting, windbreaks, etc. are arranged around the building based on experience, and the building wind countermeasure arrangement pattern is converted into an analysis model. Then, this analysis model is numerically analyzed to evaluate the wind environment.

  The second method is a method of producing a reduced model for measures against winds near the building and the building, and conducting a wind tunnel experiment using the reduced model. That is, windproof planting and windbreaks are arranged around the building based on experience, and the building wind countermeasure arrangement pattern is modeled as a reduced model. Then, the wind environment is evaluated based on the results of the wind tunnel experiment.

JP 2003-203194 A

However, the first method has a problem that the calculation time becomes enormous because numerical analysis is performed by modeling an analysis pattern for each arrangement pattern of the building wind countermeasures.
In the second method, it takes time and money to produce a reduced model and measure the wind environment. Furthermore, many experimental cases were required to compare the effectiveness of each building countermeasure.
Therefore, in the above method, it is necessary to rely on the designer's experience in order to obtain a more effective building-like countermeasure plan. It was over.

  An object of the present invention is to provide a wind environment countermeasure examination method capable of quickly determining an effective building wind countermeasure.

  The wind environment countermeasure examination method according to claim 1 (for example, wind environment countermeasure examination method 1 described later) models a space around a building (for example, a later-described planned building 11) and winds around the building. An improvement target point (for example, an improvement target point 13 to be described later) is provided as an environment improvement target, and a plane map (for example, plane maps 20, 20A to 20C to be described later) is generated around the building, and the plane map is generated. An initial procedure (for example, steps S1 to S6, which will be described later) for providing a wind countermeasure examination area which includes a plurality of unit areas (for example, unit areas 16, 21 which will be described later) and which can be arranged with a shield, When the wind blows from the wind direction of the wind, the wind path to the point to be improved is obtained as a reverse flow line (for example, the reverse flow line 14 described later), and the reverse flow line in the wind countermeasure examination area is the shielding object. A range that passes through the height (for example, an influence range 15 to be described later) is extracted, and for each unit area of the extracted range, an index indicating the magnitude of the influence of the wind of the predetermined wind direction at the improvement target point. An influence value assigning procedure for assigning an influence value (for example, step S9 to be described later) and the influence value assigning procedure are repeatedly executed for all wind directions and all improvement target points, and for each unit area of the wind countermeasure examination area , An iterative procedure (for example, steps S7, S8, S10 described later) for accumulating the applied influence values to obtain an influence accumulation value, and the influence accumulation value in each unit area of the wind countermeasure examination area of the plane map. And a display procedure (for example, steps S11 to S13 to be described later).

  The wind environment countermeasure examination method according to claim 2, wherein the shielding object is a tree (for example, a tree 12 described later), and the height of the shielding object is a height of the tree. .

  The wind environment countermeasure examination method according to claim 3, wherein the shield is a kite (for example, a kite 17 described later), and the height of the shield is a height of the kite. .

  According to the present invention, first, the backflow line that reaches the point to be improved is obtained. Then, the range where the backflow line passes through the height of the shield is extracted from the wind countermeasure examination area, and the influence value at the point to be improved is assigned to each unit area of the extracted range, and the cumulative effect value is calculated. Ask.

  In the wind countermeasure examination area, the wind that has passed through the height of the shield on the specific unit area flows along the reverse flow line and reaches the improvement target point. Therefore, the wind environment at the point to be improved can be improved by arranging the shielding object on the specific unit area. Therefore, by assigning an influence value at the point to be improved to this specific unit area, the effectiveness of the shield on each unit area is quantified. Users only need to find a unit area with a high cumulative effect value and place a shield on this unit area, so it is possible to determine effective building wind measures in a short time and at a low cost in order to reduce strong winds generated locally. it can.

  The wind environment countermeasure examination method according to claim 4 is characterized in that the influence value is a cumulative frequency that is a ratio at which the wind speed becomes a predetermined value at the point to be improved.

  According to this invention, the cumulative frequency at the point to be improved is used as the influence value. The cumulative frequency is the ratio of the wind speed used for wind environment evaluation to a predetermined value, and is an indicator of the bad wind environment, so the cumulative frequency can be used to appropriately determine the magnitude of the wind effect at the point to be improved. Can be quantified.

  According to the present invention, the influence value at the point to be improved is calculated for each unit area, and the effectiveness of the shielding object on each unit area can be quantified. Therefore, if the shielding object is arranged in the unit area having a high accumulated effect value, Well, it is possible to determine building wind countermeasures for reducing locally generated strong winds in a short time and at low cost.

It is a flowchart of the wind environment countermeasure examination method which concerns on 1st Embodiment of this invention. It is a typical top view of the mesh for evaluation used for the wind environment countermeasure examination method concerning the embodiment. It is a typical side view which shows an example of the tree used for the wind environment countermeasure examination method which concerns on the said embodiment. It is a typical top view which shows an example which displayed the influence accumulation value on the plane map used for the wind environment countermeasure examination method which concerns on the said embodiment. It is a typical top view which shows the comprehensive map used for the wind environment countermeasure examination method which concerns on the said embodiment. It is a flowchart of the improvement object point extraction procedure of the wind environment countermeasure examination method which concerns on the said embodiment. It is a figure which shows an example of the cumulative frequency of 16 wind directions of the lattice point with the wind environment countermeasure examination method which concerns on the said embodiment. It is a figure which shows an example of the wind environment evaluation parameter | index used for the wind environment countermeasure examination method which concerns on the said embodiment. It is a flowchart of the influence value provision procedure of the wind environment countermeasure examination method which concerns on the said embodiment. It is a typical top view which shows an example of the backflow line of the wind environment countermeasure examination method which concerns on the said embodiment. It is a typical side view which shows an example of the backflow line of the wind environment countermeasure examination method which concerns on the said embodiment. It is a part of flowchart of the wind environment countermeasure examination method which concerns on 2nd Embodiment of this invention. It is a typical side view showing an example of a kite used for a wind environment measures examination method concerning the embodiment.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description of the embodiments, the same constituent elements are denoted by the same reference numerals, and the description thereof is omitted or simplified.
[First Embodiment]
FIG. 1 is a flowchart of a wind environment countermeasure examination method 1 according to the first embodiment of the present invention.
The wind environment countermeasure examination method 1 is for determining the arrangement of trees as a wind countermeasure for a planned building.
In step S1, the wind environment around the planned building is analyzed by three-dimensional fluid analysis (hereinafter CFD analysis: Computational).
Fluid Dynamics)
Specifically, a CFD mesh is generated around the planned building. The CFD mesh is a mesh formed of a structural grid such as a hexahedron or a cube, an unstructured grid such as a tetrahedron or a triangular prism. By this CFD analysis, the wind speed value of each lattice point of the CFD mesh is obtained.

In step S2, a space around the planned building is modeled to generate a three-dimensional examination mesh.
FIG. 2 is a schematic plan view of the evaluation mesh 10.
This examination mesh 10 is formed around the planned building 11. The examination mesh 10 has a lattice shape different from the above-described CFD mesh, and spreads in a planar shape at a predetermined height (for example, 1.5 m) from the ground surface.

In step S3, an improvement target point extraction procedure is executed based on the wind environment obtained by CFD analysis, and a group of improvement target points is extracted from the lattice points of the examination mesh. This improvement target point extraction procedure will be described in detail later.
In the present embodiment, improvement target points are extracted using the wind environment evaluation method by Murakami, and three types of groups of improvement target points are extracted.
Specifically, among all lattice points of the examination mesh, a group of lattice points having a probability that the daily maximum instantaneous wind speed of 10 m / s exceeds a predetermined value is set as a first group.
Similarly, groups of lattice points at which the probability of exceeding the daily maximum instantaneous wind speeds of 15 m / s and 20 m / s is equal to or greater than a predetermined value are defined as second and third groups.

  In step S4, the examination mesh is viewed in plan to generate a plane map that models the space around the planned building. The number of plane maps is the same as the number of grid point groups. Therefore, in this embodiment, three plane maps are generated.

  In step S5, the user selects a wind countermeasure examination area, which is an area where trees can be arranged, from the planar map. This wind countermeasure examination area is composed of a plurality of rectangular unit areas.

In step S6, tree height data is input. Specifically, for example, as shown in FIG. 3, the height TH of the tree 12 is input. Thereby, the part used as the shielding object in the tree 12 becomes a part below the height TH.
Therefore, if a space that can be shielded by trees as a shielding object is a shieldable space, the space that can be shielded by trees in the plan map is a portion within the wind countermeasure examination area and having a height TH or less.

In step S7, improvement target points of the first group are set as initial settings.
In step S8, as an initial setting, one improvement target point is set from the set group, and one wind direction is set from the 16 wind directions.
In step S9, for the set improvement target point and the wind direction, the influence value is added and the influence value is calculated, and cumulatively added to each unit area in the wind countermeasure examination area to obtain the influence cumulative value. This influence value provision procedure will be described in detail later.

  In step S10, it is determined whether or not the calculation of influence values has been completed for all the improvement target points included in the set group and for all 16 wind directions. When this determination is No, the improvement target point or the wind direction is changed, and the process returns to step S9. When the determination is Yes, the process proceeds to step S11.

In step S11, since the influence accumulation value is calculated for all the improvement target points included in the set group, the magnitude of the influence accumulation value is expressed by the color intensity on the wind countermeasure examination area on the plane map 20. .
For example, as shown in FIG. 4, the magnitude of the influence accumulated value is expressed by the color intensity in the unit area 21 constituting the wind countermeasure examination area on the plane map 20.

  In step S12, it is determined whether or not the generation of the planar map has been completed for all groups. If this determination is No, the group is changed, and the process returns to Step S8. If Yes, the process moves to Step S13.

  In step S13, three types of plane maps have been generated. For example, as shown in FIG. 5, these three types of maps 20A to 20C are combined to generate a comprehensive map 30.

  In step S14, a tree is arranged in the dark unit area of the wind countermeasure examination area while looking at the comprehensive map 30.

Next, the improvement target point extraction procedure of step S3 will be described in detail with reference to the flowchart of FIG.
In step S31, the excess probability of the lattice point of the examination mesh is calculated based on the wind environment obtained by the CFD analysis.
Specifically, for each grid point of the study mesh, using the CFD analysis results and weather statistics such as wind direction frequency and Weibull parameters, the cumulative frequency of the wind speed used for wind environment evaluation below the predetermined value is calculated. Calculate for each of the 16 wind directions.
Specifically, the cumulative frequency at which the daily maximum instantaneous wind speed is 10 m / s, 15 m / s, or 20 m / s or less is used. For example, the cumulative frequency of the daily maximum instantaneous wind speed of 10 m / s or less means the ratio of the day when the daily maximum instantaneous wind speed in a predetermined wind direction is 10 m / s or less in the unit period.
FIG. 7 is a diagram showing the cumulative frequency of 16 wind directions at a certain grid point.

  Next, for the three types of maximum daily instantaneous wind speeds at each grid point of the study mesh, the sum of the cumulative frequencies of 16 wind directions is obtained. The higher the sum of accumulated frequencies, the better the wind environment. Three total sums of the cumulative frequencies are obtained for each grid point.

Next, the sum of the cumulative frequencies is subtracted from 1 to obtain an excess probability. For example, the excess probability when the daily maximum instantaneous wind speed is 10 m / s is the rate at which the daily maximum instantaneous wind speed exceeds 10 m / s. The lower the excess probability, the better the wind environment. Three excess probabilities are obtained for each grid point.
In FIG. 7, the sum of the accumulated frequencies is 0.677747, 0.98536, and 0.99993, and the excess probabilities are 0.32253, 0.01464, and 0.00007.

In step S32, the wind environment of the lattice points is ranked based on the excess probabilities of the lattice points of the examination mesh.
First, a wind environment evaluation index is prepared. The wind environment evaluation index is obtained by ranking the wind environment based on the excess probability for each maximum instantaneous wind speed of each day. The lower the excess probability, the lower the rank, and the better the wind environment.

FIG. 8 is a diagram illustrating an example of a wind environment evaluation index. According to the wind environment evaluation index, ranking is performed for each daily maximum instantaneous wind speed at each lattice point of the examination mesh. That is, three ranks are assigned to one grid point.
Not limited to this, the most severely determined rank among the three types of ranks of each grid point may be used as the rank of the grid point.

In step S33, based on the wind environment rank, improvement target points to be improved in the wind environment are extracted from the lattice points of the examination mesh.
For example, grid points with rank 3 or higher are extracted as improvement target points.
Here, a group of lattice points extracted based on the respective ranks of the daily maximum instantaneous wind speeds of 10 m / s, 15 m / s, and 20 m / s are defined as first to third groups.

Next, the influence value provision procedure of step S9 will be described in detail with reference to the flowchart of FIG.
In step S91, based on the result of the CFD analysis, the back stream line of the set improvement target point when the wind blows from the set predetermined wind direction is calculated. The reverse flow line is a wind path to the point to be improved. FIG. 10 and FIG. 11 are a schematic plan view and a side view showing an example of the backflow line 14 reaching the improvement target point 13.

In step S92, the unit area constituting the set wind countermeasure examination area is determined as an influence range in which the backflow line passes through the height position of the shield.
10 and 11 show the backflow line 14 passing through the height of the tree 12. The reverse flow line 14 passes through a portion of the influence range 15 up to the height TH. The influence range 15 is a portion indicated by oblique lines in FIG. 10 and is composed of a plurality of unit areas 16.
The wind that has passed through the height of the tree on the influence range flows along the reverse flow line and reaches the improvement target point. Therefore, the wind environment at the improvement target point can be improved by arranging the tree on the influence range.

In step S93, the influence value at the improvement target point is assigned to each of the unit areas constituting the influence range. The influence value is an index indicating the magnitude of the influence of the wind in a predetermined wind direction at the improvement target point, and uses an accumulated frequency.
When an influence value has already been assigned to each unit area, the influence value assigned this time is cumulatively added, and a value obtained by cumulatively adding the influence value is set as an influence cumulative value.

According to this embodiment, there are the following effects.
(1) A reverse flow line 14 reaching the improvement target point 13 is obtained, and an influence range 15 in which the reverse flow line 14 passes through the height of the shield is extracted from the wind countermeasure examination area, and a unit area of the extracted influence range 15 About each of 16, the influence value in the improvement object point 13 is provided, and an influence accumulation value is calculated | required.
By assigning the influence value at the improvement target point 13 to the unit area 16 of the influence range 15, the effectiveness of the tree 12 on the influence range 15 is quantified. Since the user only needs to find a unit area 16 having a high cumulative effect value and place the tree 12 as a shield on the unit area 16, a short-term countermeasure against a building wind effective for reducing the strong wind generated locally can be achieved. Decide on time and cost.

  (2) The cumulative frequency at the improvement target point 13 is used as the influence value. The cumulative frequency is a ratio at which the wind speed used for the wind environment evaluation becomes a predetermined value, and is an index indicating the bad wind environment. Therefore, by using the cumulative frequency, the magnitude of the influence of the wind at the improvement target point 13 can be determined. Can be quantified appropriately.

[Second Embodiment]
FIG. 12 is a part of a flowchart of the wind environment countermeasure examination method 1A according to the second embodiment of the present invention.
The wind environment countermeasure examination method 1A is for determining the arrangement of the kite as a wind countermeasure for the planned building.
In this embodiment, the configuration of steps S5A and S6A is different from that of the first embodiment, and the other steps S1 to S4 and S7 to S14 are the same as those of the first embodiment.

  In step S5A, the user selects a wind countermeasure examination area, which is an area in which the kite can be placed, from the plane map.

  In step S6A, the heel height data is input. Specifically, as shown in FIG. 13, the height ZH of the flange 17 is input. FIG. 13 shows a reverse flow line 14 that reaches the point to be improved 13. As a result, the shieldable space by the eaves in the plane map becomes a portion with the height ZH in the wind countermeasure examination area.

  According to the present embodiment, there are the same effects as the above (1) and (2).

It should be noted that the present invention is not limited to the above-described embodiment, and modifications, improvements, etc. within a scope that can achieve the object of the present invention are included in the present invention.
For example, in steps S3 and S4 of the present embodiment, the wind environment evaluation method by Mr. Murakami is adopted, but not limited thereto, the wind environment evaluation method by the Wind Engineering Laboratory may be adopted.

  Specifically, in step S3, two wind speeds of 55% cumulative frequency and 95% cumulative frequency are obtained for each lattice point. Here, for example, a wind with a cumulative frequency of 95% is 4.6 m / s, a wind of 4.6 m / s or less is 95% of the whole, and the remaining 5% is a wind exceeding 4.6 m / s. It means that.

Next, the wind environment of the grid points is ranked based on the wind speed with the cumulative frequency of 55% and the wind speed with the cumulative frequency of 95%, and a group of grid points extracted based on the rank of the wind speed with the cumulative frequency of 55% is the first. A group is set, and a group of lattice points extracted based on a wind speed rank with a cumulative frequency of 95% is defined as a second group.
In step S4, two plane maps are generated according to the number of lattice point groups.

DESCRIPTION OF SYMBOLS 1 ... Wind environment countermeasure examination method 10 ... Examination mesh 11 ... Planned building 12 ... Tree 13 ... Improvement target point 14 ... Backflow 15 ... Influence range 16, 21 ... Unit area 17 ... 庇 20 ... Plane map 20A-20C ... Map 30 ... Comprehensive map

Claims (4)

The space around the building is modeled to provide improvement target points for improvement of the wind environment around the building, a plane map is generated around the building, and a plurality of unit areas are created on the plane map. An initial procedure for establishing a wind countermeasure study area that can be placed and a shield,
A range in which the backflow line passes through the height of the shield in the wind countermeasure examination area by obtaining a wind path to the improvement target point when the wind blows from the predetermined wind direction to the building. And for each of the unit areas of the extracted range, an influence value giving procedure for giving an influence value that is an index indicating the magnitude of the wind influence of the predetermined wind direction at the improvement target point;
Repeatedly performing the influence value giving procedure for all wind directions and all points to be improved, and for each unit area of the wind countermeasure examination area, repeatedly adding the assigned influence values to obtain an accumulated effect value; and
And a display procedure for displaying the magnitude of the cumulative effect value in each unit area of the wind countermeasure study area of the plane map. The shield is a tree;
The wind environment countermeasure examination method according to claim 1, wherein the height of the shield is a height of the tree. The shield is a cocoon,
The wind environment countermeasure examination method according to claim 1, wherein the height of the shield is a height of the ridge.   The wind environment countermeasure examination method according to any one of claims 1 to 3, wherein the influence value is a cumulative frequency that is a ratio at which the wind speed becomes a predetermined value at the improvement target point.

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