A novel particle tracking and break-up detection algorithm: application to the turbulent break-up of bubbles

A new method has been developed to measure experimentally the break-up properties of bubbles. The technique is based on the application of a particle tracking velocimetry algorithm to high-speed video images not only to measure the velocity of the bubbles, but also to detect the break-up events. Thus the algorithm is able to associate every broken bubble with the daughter bubbles formed upon their corresponding break-up. Moreover, the lifetime, as well as the number and size of fragments resulting from the break-up process, can be measured for a large number of bubbles. Statistical processing of the information collected allows us to compute the break-up frequency and daughter size distribution of the bubbles as a function of the bubble size and the mean properties of the base flow. The method has been employed to study the break-up of a cloud of bubbles injected at the central axis of a turbulent water jet. Experimental results for the break-up frequency and daughter bubble size distribution are also presented to illustrate the performance of the technique.