Unsteady indoor airflow analysis of non-isothermal natural ventilation using domain decomposition technique with LES

¹ Osaka University, Department of Architectural Engineering, 2-1, Yamadaoka, Suita, Osaka, Japan
² Obayashi Corporation, Technical Research Institute, 4-640, Shimokiyoto, Kiyose, Tokyo, Japan

^* Corresponding author: kobayashi@arch.eng.osaka-u.ac.jp

Abstract

The paper presents a CFD technique named Domain Decomposition Technique which enables analysing indoor airflow for natural ventilation. Since it has been studied for the isothermal condition with RANS model, the present paper aims to propose a method to apply it for the non-isothermal condition using Large Eddy Simulation (LES). The technique is composed of three steps, i.e., 1) outdoor simulation to obtain boundary conditions at possible opening locations, 2) calculating three components of velocity at the openings as boundary conditions, and 3) indoor airflow analysis. Two cases of the wind direction are studied in the paper, i.e., wind is assisting/opposing the buoyancy. By comparing the indoor temperature and velocity distribution between the whole domain analysis and DDT, the applicability of the DDT is studied.