Enhancing control of air bubbles in water flows through laser-based surface wettability patterning

Air bubble injection has been a widely studied method for reducing frictional drag in fluid flows, especially in the marine industry. However, the lack of control over air bubble stability, size, and shape has hindered its widespread adoption. This study investigates the use of laser-based surface wettability modification techniques to address these challenges by enhancing control over air bubble behavior in water flows. We processed metal plates using nanosecond laser and chemical immersion to create wettability patterns consisting of regions of either superhydrophobicity or superhydrophilicity. Water tunnel experiments were conducted to observe the behavior of air bubbles over these different wettability patterns. The results revealed that surface wettability can be used to control the size and spatial distribution of air bubbles, which can enhance the energy cost-benefit of drag reduction methods in the marine industry. Moreover, this research offers new insights into the potential of laser-based surface wettability modification as a solution for improving the control of air bubble behavior in large-scale applications.