抄録
The turbulent mass exchange through an opening of a circular pipe is studied experimentally. The mass is transported exclusively by the turbulence generated in the shear layer between pipe flow and the surroundings. To make precise measurements of the total amount of diffused tracer gas across the opening, a new method using a closed loop conduit with an opening is developed. As dimensionless parameters which represent the intensity of turbulent diffusion, the diffusion factor, the interference factor and the breathing rate are newly defined, and the influence of opening length and shape on these parameters is quantitatively clarified. Velocity and concentration distributions are also obtained to examine the structure of the turbulent shear layer in the opening.
