Image measuring for the water level and bubble shape and velocity at the transition phenomenon from open channel to pipe flow

Abstract

Various two-phase (water-air) flows occur in underground pipes like large sewer. When the pipe is filled gradually with water at flood, air may become large bubble. Then, for the purpose of researching the bubble behavior at the transition phenomenon from open channel to pipe flow, we developed the laboratory system for automatic controlled inlet discharge and image measuring water level and bubble shape and velocity. The system was constructed by motor valves, magnetic flow meters, video cameras etc. The maximum error is less than 3%. The system is useful for research of the transition phenomena.