Abstract
It is important to estimate an instantaneous high concentration for a combustible gas or an odor gas diffusion. To develop a prediction method of instantaneous high concentration in highly turbulent region nearby buildings, wind tunnel tests are conducted. As a building model, a cube is adopted. As a tracer, ethane is released from an outlet at the top of the cube or a stack behind the cube. The time series concentration data are measured around and in the downstream of the cube with a high-speed-hydro-carbon meter. From the data, time averaged concentration, variances of concentration, probability density functions and intermittencies are investigated. Irrespective of the source or receptor position, the probability density functions of the concentration become the log normal distribution except for the area where the intermittency is high.
