抄録
In this study, gas transfer velocity through free surface is investigated in open channel flow with a series of spur dikes. Spur dikes formed closed dead-water zones between the neighboring members. The slow-speed circulation observed in such cavity zones is quite different from high-speed mainstream. Therefore, the cavity zones and the mainstream are assumed to have different reaeration coefficient. The reaeration coefficients are evaluated by means of laboratory measurements. The measurement theory is also specially developed together with consideration of gas transfer through the junction between main-channel / side-cavity. It is found out from present results that reaeration coefficient depends strongly on the aspect ratio (width/length) of dead water zones under same hydraulic condition.
