Host: The Japan Society of Mechanical Engineers
Name : [in Japanese]
Date : November 11, 2020 - November 13, 2020
Clustering of spherical bubbles rising along an inclined flat wall has been investigated experimentally to analyze the bubble-bubble interaction. To avoid bubble coalescences, the electrolyte (MgSO4) solution and the surfactant (Triton X-100) solution are utilized as a liquid phase. In MgSO4 solution, free-slip boundary condition of bubble surface is maintained, on the other hand, the boundary condition of the surface of rising bubbles in Triton X-100 solution becomes no-slip due to well-know Marangoni effect. The development of bubble clusters and the bubble-bubble interaction of bubbles are discussed through the statistical analysis of the bubble velocities and the distance between neighboring bubbles. The bubbles tend to be arranged horizontally as they rise, which induces bubble cluster formation. The horizontally aligned bubbles tend to rise more stably in case of the no-slip condition. The drag coefficient increases with increasing number of horizontally aligned bubbles. When the approach distance L is short, the effect of wake-induced lift is confirmed only in the case of free-slip condition. In case of no-slip condition. Even in the longer separation distance of side-by-side bubbles, the separation velocity was still induced on no-slip bubbles.
