Development of a Digital Fringe Projection Technique to Characterize the Transient Behavior of Wind-Driven Droplet/Rivulet Flows

Thin film flows naturally arise in a wide variety of industrial and environmental problems ranging from microchip manufacturing, structured packing to lava flows in geology. In particular, wind-driven flows of liquid films are of great interests for deeper understanding of aircraft icing and better design of anti-icing and de-icing strategies. Currently, most thickness mapping techniques involves complicated experimental layout and expensive measuring facilities, for example, photo-luminescence, and stereoscopic techniques. In this study, we successfully applied Fourier transform profilometry for the thickness measurement of wind-driven droplet flows. This technique has been very popular in many fields, like 3D sensing, object recognition, but less known in the fluid dynamics community. It features simple experimental layout, low cost, high spatial resolution, and real time thickness measurement. All these merits motivate us to explore wider and better application of this technique and its variants in the field of fluid mechanics.