Abstract
A plethora of studies have investigated the motion of liquid droplets in microtubes or microchannels as technologies in microfluidics developed rapidly in recent decades. Most computational studies on this topic assumed smooth inner surface for the fluid conduit. However, there are few studies that consider the roughness of the inner surface that could affect the droplet motion, especially for the cases in which the roughness size is comparable to that of the droplet. In this study, we employ a 3D spectral boundary element method for interfacial dynamics to examine the droplet translation, migration, and deformation in a micron-sized cylindrical tube with a rough inner surface. The roughness feature of the surface is comparable to the size of the droplet and is simulated with sinusoidal functions. The computational results show that the surface roughness significantly affects the behavior of a deformable droplet, including its deformation as well as the speed of translation. The results of this study could provide contribution to the development of microfluidics.
