Analysis of wind-induced inflow and outflow through a single opening using LES & DES

Abstract

In order to investigate induced flow properties through a single opening, large-eddy simulations (LES) are performed on ventilated air through the single opening of a room. In this flowfield, the outdoor air flows parallel to the wall and to the opening, and the room airflow is induced by the outdoor flow through the opening. Both the outdoor and indoor airflows are simultaneously simulated. Firstly, the dependency of the induced room airflow to the shape of the opening is investigated (by changing the shape of the opening). Secondly, the distributions of mean and turbulent variables at the boundary plane of the opening are investigated. It is clarified that the shape of the opening and the resultant mixing layer thickness developed along the opening boundary plane affect the characteristics of the air exchange rate and the feature of the room's airflow. In the case of a longer opening, the change in air exchange characteristics is apparent. Furthermore, detached-eddy simulation (DES) was performed on the same flowfields in order to examine the applicability of DES to building ventilation analysis. Two types of calculation (LES calculation and DES calculation with the same grid) were performed. It is concluded that DES over-estimates the sub-grid scale viscosity in the LES region, but the difference in room mean property between both cases is low.