壁面近傍を上昇する変形気泡に働く力の理論解析 : 流体工学,流体機械

概要

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The prediction of the behavior of a rising bubble near a wall is very important to control a bubbly flow in chemical reactor, or to develop the drag reduction devices using micro bubbles etc. In the present study, theoretical analysis of a deformed bubble rising near the wall is conducted. In the former experimental studies, there is a qualitative discrepancy between the theory for a spherical bubble and experimental results in the low Reynolds number cases. It is well-known that there is no lift force acting on spherical bubble under the creeping now approximation due to the kinematic reversibility. Therefore, in case of the theory of a spherical bubble, weak inertia effect must be taken into account to obtain a lift force. However, there is another possibility to have a lift force, that is, a deformation of bubble. In the present study, to estimate the effect of deformation, we conduct the donlaln perturbation analysis using Lamb's general solution for Stokes flow. The expression for the lift force due to the deformation is shown with the higher order extension. It is also shown that the slight deformation effect becomes more important as a bubble rises closer to the wall and the effect will become larger than that of small inertia below a certain distance from the wall.
2001-05-25