Bubble floatation, burst, drainage, and droplet release characteristics on a free surface: A review

The phenomenon of a bubble bursting to generate droplets exists in industrial and environmental systems and has a subtle impact on our daily lives. A bubble generated by gas injection or heating rises to the free surface and undergoes floating, drainage, and eventually bursting processes to produce film and jet droplets. The interrelated processes make it difficult to understand the characteristics of a bubble burst. Thus, a summary of the individual stages of a single bubble from generation to burst is necessary. First, we describe the calculation method and simple expressions for the shape of a bubble floating on a free surface. Next, we discuss the bubble drainage model and its influencing factors as this directly determines the time evolution of the film thickness. As an essential factor that affects the film thickness, the bubble drainage time is defined as the bubble lifetime. We compare the bubble lifetime distributions in the published literature and explore the associated influencing factors. Then, we investigate the bubble bursting dynamics and focus on the bubble film opening process once a hole appears on its surface. As a legacy of bubble burst, we explore the production process, size, and number of film and jet droplets. Finally, we discuss the enrichment phenomenon and the enrichment factors of film and jet droplets when releasing particles entrained by droplets. This review considers a series of processes for bubble burst to generate droplets and concentrates on the mechanism and experimental correlations with a summary and future prospects.