Dynamics of Droplets

Capturing non-Newtonian power-law drops by horizontal thin fibers with circular cross‐ section in a quiescent media can be studied in this chapter. The case is simulated using volume of fluid (VOF) method providing a notable reduction of a computational cost. Open source OpenFOAM software is applied to conduct the simulations. This model is an extension of the one developed earlier by Lorenceau, Clanet, and Quéré [1]. To vali‐ date the model, water drops affecting a fiber of radius 350μm were simulated and thresh‐ old drop radiuses were obtained regarding to the impact velocity. These results agreed well with the experimental data presented by Lorenceau et al. [1]. In the next step, nonNewtonian power-law drops landing on thin fiber of radius 350μm were simulated. The final goal of this study was to obtain the threshold velocity and radius of a drop that is completely captured by the fiber. Threshold radiuses for both shear-thinning and shearthickening drops were obtained and compared with corresponding Newtonian drops. Results show that the threshold radius of drop increases in a fixed velocity as n, powerlaw index, increases. Furthermore, shear-thinning nature of the drop leads to instabilities in high Reynolds numbers (Re) as it influences the fiber.