Set a wind direction and speed, and computational fluid dynamics shows how buildings change the flow. Use it to check wind around buildings and in early planning.
Steps
- In 解析追加 choose 風況解析 (wind) and a case (Running an analysis).
- Press 地図上で条件を設定 and pick the centre with 中心 (Center). You don't draw an area. Set the conditions below in the left panel and press 確定. See Setting conditions on the map for the map steps.
- Press 計算開始 on the main screen.
Conditions
| Item | Default | Allowed | Meaning |
|---|---|---|---|
| Wind direction | N (0°) | 16 directions, 22.5° apart | Where the wind blows in from. N means a wind from the north |
| Wind speed | 10.0 m/s | 1.0–50.0 m/s, one decimal | Speed of the wind entering the area |
| Reference height | 10.0 m | 5.0–100.0 m, one decimal | The height above ground at which the wind speed applies |
| Receptor height | 1.5 m | 1.0–200.0 m, one decimal | Height of the plan-view result. 1.5 m for pedestrians |
| Roughness category | IV | I–V | Ground conditions upwind (table below) |
| Category | Ground |
|---|---|
| I | Almost no obstacles |
| II | Farmland or grassland, scattered low buildings |
| III | Town of low-rise buildings |
| IV | Town of mid-rise buildings (4–9 storeys) |
| V | City of high-rise buildings (10+ storeys) |
An out-of-range value shows the reason under the field, and 確定 reports that the input has errors.
Choose a lower roughness category for open ground upwind and a higher one for dense city. The rougher the ground, the weaker the wind near it.
Notes
As also shown on screen:
- Computational fluid dynamics on the published city model, using LOD1 building data and the OpenFOAM solver.
- Buildings are reproduced within a 300 m radius of the centre.
- Each run returns a plan view about 200 m square (at the receptor height) and vertical sections through the centre, along and across the wind direction.
- After city-model updates, some places may be computed with buildings that differ from those displayed.
- Some conditions are simplified, for example terrain relief is ignored.
Results
The case and these layers appear under サービス → 風況解析:
| Layer | Shows |
|---|---|
| Ground-level wind speed and vectors | Wind speed and direction at the receptor height |
| Horizontal section wind speed and vectors | Speed and direction on a horizontal cut |
| Vertical section wind speed and vectors | Speed and direction on a vertical cut |
Click a result on the map to see the wind speed there (for example 0.53 m/s). Default colours cover 0–25 m/s with breaks at 25, 20, 15, 10, 8, 6, 4, 2 and 1 m/s. To change them, see Editing display styles.