Artificial generation of inflow turbulence with wind and scalar fluctuations for large-eddy simulation in urban environment

2016 Fiscal Year Final Research Report

• Project/Area Number: 26420578
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Architectural environment/Equipment
• Research Institution: Tokyo Institute of Technology (2015-2016); Tohoku University (2014)
• Principal Investigator: Okaze Tsubasa 東京工業大学, 環境・社会理工学院, 准教授 (40709739)
• Co-Investigator(Renkei-kenkyūsha): YOSHIE Ryuichiro 東京工芸大学, 工学部, 教授 (60386901)
• Research Collaborator: NARITA Kenichi 日本工業大学, 工学部, 教授 (20189210)
• Project Period (FY): 2014-04-01 – 2017-03-31
• Keywords: ラージ・エディ・シミュレーション / 流入変動風 / 大気安定度 / コレスキー分解 / 都市風環境 / 都市温熱環境 / 乱れの特徴的長さスケール / 乱れの特徴的時間スケール

Outline of Final Research Achievements

This study proposed a new method for generating turbulent fluctuations in wind velocity and scalars, such as temperature and contaminant concentration, based on a Cholesky decomposition of the time-averaged turbulent flux tensors of the momentum and the scalar. The artificial turbulent fluctuations generated by this method satisfy not only the prescribed profiles for the turbulent fluxes of the momentum and the scalar but also the prescribed spatial and time correlations.
Then, the artificially generated turbulent fluctuations of wind velocity and air temperature was applied as inflow boundary conditions for a large-eddy simulation of a non-isothermal flow around a building. The mean wind velocity and mean air temperature predicted from the large-eddy simulation agreed well with the experimental results. The turbulent kinetic energy and the fluctuation of the air temperature also corresponded fairly well with the experiment except for the region immediately behind the inflow boundary.

Free Research Field

建築環境・設備