Visualization of bubble-fluid interaction by a moving object flow image analyzer system.

This paper deals with interaction between a bubble and fluid around it, visualized by a moving object flow image analyzer (MOFIA) consisting of a three-dimensional (3D) moving object image analyzer (MOIA) and two-dimensional particle image velocimetry (PIV). The experiments were carried out for rising bubbles of various sizes and shapes in stagnant water in a vertical pipe. In the MOFIA employed, 3D-MOIA was used to measure bubble motion and PIV to measure fluid flow. The 3D position and shape of a bubble and the velocity field were measured simultaneously. The experimental results showed that the interaction was characterized by the shape, size and density of a bubble. Concretely, they showed the characteristics of bubble motion, wake shedding, and flow field.