The Coanda Effect on Bubbling Jet behind a Horizontally Placed Circular Cylinder

Abstract

The motions of bubbles and liquid behind a circular cylinder placed horizontally in a vertical water-air bubbling jet were experimentally investigated. Bubbles approaching the cylinder were separated by the cylinder in the two ways along the side wall of the cylinder, and they gathered together again at a certain distance from the cylinder due to the Coanda effect. This situation was confirmed from the measurements of gas holdup and mean water velocity components. The mean bubble diameter behind the cylinder became small because disintegration of bubbles took place around the cylinder. The mean bubble rising velocity also became very low behind the cylinder. The horizontal spreading of the bubbling jet was significantly suppressed by the cylinder.