Numerical simulation of muco-ciliary clearance: immersed boundary-lattice Boltzmann method

Immersed boundary-lattice Boltzmann method is used to simulate muco-ciliary clearance process. Two-layer fluid model consisting of the mucus layer as a viscoelastic fluid and periciliary liquid (PCL) layer as a Newtonian fluid has been simulated here. The major thrust of this study is on elucidating the role of the viscoelastic behavior of mucus on the muco-ciliary transport and for this purpose an Oldroyd-B model is used as the constitutive equation of mucus. Numerical simulations have been performed to investigate the effects of mucus viscosity, cilia beat frequency, depth of PCL and mucus and surface tension of the PCL-mucus interface on muco-ciliary transport process. Our results show that in the specific value of mucus viscosity, increasing in the Newtonian contribution of mucus viscosity has a great effect on the mean mucus velocity. Increasing cilia beat frequency is the second parameter that can increase mucus flow. Decreasing mucus relaxation time and the depth of PCL and mucus, especially at lower values can decrease mean mucus velocity. Results also show that mucus viscosity and surface tension of the PCL-mucus interface does not have a great effect on the mucus flow.