Numerical Study on the Improvement of a Heavy Gas Dispersion Model Based on a Shallow Layer Approarch

2016 Fiscal Year Final Research Report

• Project/Area Number: 26350467
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Social systems engineering/Safety system
• Research Institution: National Institute of Maritime, Port and Aviation Technology
• Principal Investigator: OKA HIDEYUKI 国立研究開発法人海上・港湾・航空技術研究所, その他部局等, 研究員 (80399518)
• Project Period (FY): 2014-04-01 – 2017-03-31
• Keywords: 浅層モデル / 高密度ガス / 大気拡散

Outline of Final Research Achievements

This study is concerned with computer models for atmospheric dispersion of denser-than-air gas. In particular, we focus on a shallow-layer approach based on shallow water equations out of three types of modeling approaches. One of available computer codes based on a shallow-layer model, Twodee-2 (Folch, et al., 2009), is employed to evaluate and improve this model. This code can deal with heavy gas dispersion phenomena induced by surrounding airflow. However, it has been confirmed that it does not work in the simulation of a heavy gas current under its own weight on a sloping terrain. Therefore, a discretization scheme for advection terms of model equations is modified to a simple, second-order upwind scheme. In addition, an air entrainment model is modified to take account of the heavy gas flow velocity instead of the surrounding airflow. As a result, it has been found that numerical results by this modified Twodee-2 code can nicely reproduce wind tunnel experimental data.

Free Research Field

計算流体力学