A WIND TUNNEL EXPERIMENT ON TRACER GAS CONCENTRATION FLUCTUATION NEAR A CUBICAL MODEL BUILDING

Abstract

A wind tunnel experiment was conducted to investigate the effects of a building on tracer gas concentration fluctuation in a wake region of a cubic model perpendicular to the wind direction. Measurements were carried out in a plume emitted from a point source on the model roof using a high-frequency-response flame ionization detector. The concentration fluctuation intensity is approximately constant at a value between 0.4 and 0.5 in a building wake. The peak-to-mean concentration ratio in a wake agrees well with that estimated from the lognormal distribution and is always about 5 times the concentration fluctuation intensity.