Abstract: The mathematical model describing the influence of periodical inertial forces introduced by rolling on bubbles was presented. The effect of radial forces including inertial and buoyancy forces on bubbles was investigated. Of all the periodical inertial forces, the centrifugal and Coriolis forces can be ignored, while the tangential force plays an important role on bubbles, reaching to its maximum when the rolling platform is at maximal rolling angle. The fluctuation amplitude of periodical inertial forces on radial direction increases with the rolling amplitude and the bubble position away from the channel inlet, and also increases with the decrease of the rolling period. By accounting for the periodical variation of buoyancy force under rolling condition, its amplitude is much larger than those of the periodical inertial forces. The fluctuation amplitude of force increases with the bubble size and is independent with the distortion of the bubble.