Analysis of gas transfer mechanisms due to air bubble and turbulence at the air-water interface

点击翻译按钮获取中文摘要

A dual-tip void probe was developed as a extension of standard single void probe. The validity of dual-tip void probe was verified and applied to bubble characteristics induced by breaking wave in the mechanically generated wave in the flume. The amount of gas transfer flowing rate instead of traditional gas transfer velocity was proposed to estimate the gas transfer rate in the surf zone, quantitatively (Kakuno, Shigematsu and Hosoi). The characteristics of turbulence in bubbly flows were measured and analyzed in the experimental facility (Asai). The droplet collision into the water surface was measured using 1 million frame per second ultra-high speed camera. The instability of thin gas film between droplet and water surface shows clear Reynolds number and Weber number dependence (Etoh). The relationship between the surface renewal process and micro scale turbulence has been measured by Particle Image Velocimetry and Laser Induced Fluorescence in a lattice turbulence (Sugihara). The simultaneous visualizations of air and water velocities were conducted in the wind-wave flume. The organized motion of air and water flows were measured and the bursting motions of air flow into the water were observed visually (Takehara, Etoh, Shigematsu and Tsujimoto). The bubble diameter distribution and bubble source functions were measured using Phase-Doppler anemometry in the wind-wave flume. The coherent bubble diameter spectra were measured under the wind-wave breaking (Mori). The field observations of bubble distributions under the wind-wave breaking were investigated using ultra sonic sensor at the upper ocean (Yoshioka). The gas transfer model at the breaking wave interface was proposed as a summary of above results (Moog).