Modeling of characteristics of concentration fluctuation by line image measurement using an atmospheric diffusion wind tunnel

2018 Fiscal Year Final Research Report

• Project/Area Number: 16K06097
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Fluid engineering
• Research Institution: Kushiro National College of Technology
• Principal Investigator: Kosugi Atsushi 釧路工業高等専門学校, 創造工学科, 准教授 (60290673)
• Project Period (FY): 2016-04-01 – 2019-03-31
• Keywords: 大気乱流拡散 / 風洞実験 / プルームの蛇行 / 相対拡散 / ライン計測 / 濃度変動特性 / 連続点源 / 一様乱流場

Outline of Final Research Achievements

Particle diffusion experiments were conducted in a short-time diffusion field where the meandering diffusion is dominant using a wind tunnel with active grid. Relative diffusion and meandering diffusion were separately measured by visualization line measurement using laser and line scan camera. Each diffusion scales, total diffusion, relative diffusion, and meandering diffusion were obtained, and it was confirmed that they almost agreed with the Gifford's theorem. The intermittency shows a different tendency in the total diffusion and relative diffusion in the downstream direction and the relationship with the meandering ratio which is the scale of the diffusion field was obtained.

Free Research Field

流体工学

Academic Significance and Societal Importance of the Research Achievements

プルームの蛇行拡散は大気拡散現象を代表する代表的な現象の一つであるが，風洞などによる定量評価が難しい側面があり，その中でも特にプルーム内部の濃度特性は計測自体が困難である．本研究では実験的にプルームの瞬間的な濃度特性を取得できる実験手法を確立できたことで，より詳細な拡散モデルの構築を行うことができると期待される．また，本研究手法をベースとして，今後は大気境界層内の拡散現象や，突風に伴う拡散現象についても評価できると考えられ，学術面における意義も大きいと考えられる．