Khodabocus MISellier MNock V2017-07-062017-07-062016Khodabocus MI, Sellier M, Nock V (2016). Slug Self-Propulsion in a Capillary Tube Mathematical Modeling and Numerical Simulation. Advances in Mathematical Physics. 2016. 1-16.1687-91201687-9139http://hdl.handle.net/10092/13672© 2016 M. I. Khodabocus et al.A composite droplet made of two miscible fluids in a narrow tube generally moves under the action of capillarity until complete mixture is attained. This physical situation is analysed here on a combined theoretical and numerical analysis. The mathematical framework consists of the two-phase flow phase-field equation set, an advection-diffusion chemical concentration equation, and closure relationships relating the surface tensions to the chemical concentration. The numerical framework is composed of the COMSOL Laminar two-phase flow phase-field method coupled with an advection-diffusion chemical concentration equation. Through transient studies, we show that the penetrating length of the bidroplet system into the capillary tube is linear at early-time regime and exponential at late-time regime. Through parametric studies, we show that the rate of penetration of the bidroplet system into the capillary tube is proportional to a time-dependent exponential function. We also show that this speed obeys the Poiseuille law at the early-time regime. A series of position, speed-versus-property graphs are included to support the analysis. Finally, the overall results are contrasted with available experimental data, grouped together to settle a general mathematical description of the phenomenon, and explained and concluded on this basis.enJournal Article2017-07-01Fields of Research::40 - Engineering::4012 - Fluid mechanics and thermal engineering::401299 - Fluid mechanics and thermal engineering not elsewhere classifiedField of Research::01 - Mathematical Sciences::0105 - Mathematical Physicshttps://doi.org/10.1155/2016/1234642