Simulations of microflows induced by rotation of spirals in microchannels

In microflows where Reynolds number is much smaller than unity, screwing motion of spirals is an effective mechanism of actuation as proven by microorganisms which propel themselves with the rotation of their helical tails. The main focus of this study is to analyze the flow enabled by means of a rotating spiral inside a rectangular channel, and to identify effects of parameters that control the flow, namely, the frequency and amplitude of rotations and the axial span between the helical rounds, which is the wavelength. The time-dependent three-dimensional flow is modeled by Stokes equation subject to continuity in a time-dependent deforming domain due to the rotation of the spiral. Parametric results are compared with asymptotic results presented in literature to describe the flagellar motion of microorganisms.