Measurement of the spatial distribution of turbulent flows within urban district at a pedestrian level

2023 Fiscal Year Final Research Report

• Project/Area Number: 20H02253
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Review Section: Basic Section 22040:Hydroengineering-related
• Research Institution: Tokyo Institute of Technology
• Principal Investigator: Inagaki Atsushi 東京工業大学, 環境・社会理工学院, 助教 (80515180)
• Co-Investigator(Kenkyū-buntansha): 小田 僚子 千葉工業大学, 創造工学部, 教授 (50553195)
• Project Period (FY): 2020-04-01 – 2024-03-31
• Keywords: 熱画像風速測定法 / 都市キャノピー層 / 大気境界層 / 多点気象観測 / ドップラーライダー / 街区 / 風速分布

Outline of Final Research Achievements

This study investigated the horizontal distribution of airflows within unban districts. This is accomplished by means of the thermal image velocimetry and multi-point observation of turbulent fluctuation. A sets of simple meteorological observation system, which is composed of sonic anemometer, temperature/humidity sensor, and solar panel, were deployed within a range of several hundred meters. These observations can measure the turbulent flow distribution neat the ground at spatial grids smaller than 1 m. It revealed that the temporal mean wind statistics, which are the mean wind speed, turbulent kinetic energy, etc. are robustly dependent on the regionally representative wind speed and directions, together with the geometries and arrangements of the surrounding buildings.

Free Research Field

都市気象、環境流体力学

Academic Significance and Societal Importance of the Research Achievements

都市街区の流れについて、近年多くの数値計算を用いた研究がなされているが、その精度評価をするための包括的な風速の観測データが必要である。本研究はそのための手法を開発し、実都市において1m以下の空間解像度での風の実測値を示したことに意義がある。また、街区内の風は大気安定度や風上影響を受けるものの街区構造の影響が特に顕著であるとの実測結果に基づき、街区構造のみで規定される速度分布を仮定した風速即時診断方法を提案した。