Statistical quantification of drop deformation behaviour and breakup initiation time in high speed air flow

In this paper, single water drop breakup in a high-speed gas flow behind shock wave, which is generated by shock tube, are repeatedly photographed under the same conditions. The laser rupture method, which have good shock wave generation timing, is adopted. The intensity values of the images are averaged to conduct statistical quantification of drop projection image thickness and volume. In early stage, drop projection image thickness and volume obtained from average intensity distribution are almost the same to drop projection image thickness and volume obtained from the original image. Additionally, we found that drop projection image volume increase rapidly at the time when the breakup initiates. Therefore, we propose a measurement method of breakup initiation time by utilizing the drop projection image volume. This breakup initiation time is compared with empirical equation of initiation time. Thus, it is shown that the proposed measurement method is valid.