Effects of Bubble Motion on Chord Length Measured by Double-Needle Conductance Probe

This study deals with effects of bubble motion on average chord length of bubbles measured by a double-needle type conductance probe system. So far, known estimation methods for bubble size are restricted to only a spherical bubble. For the estimation of deformed bubble size, the rocking motion of a bubble should be considered. Furthermore, in order to obtain the value of bubble size near the wall, the relation between the size and average chord length of bubbles should be derived taking both the restricted bubble motion and the probe position into account. The results show that taking the rocking motion of a bubble into account, the bubble size is estimated accurately for an oblate spheroidal bubble, and that the restriction of the bubble motion by the wall induces the peak in the chord length distribution, even if the bubble size is uniform.