Computational Models for Biological Locomotion in Gels
Abstract
We investigated Low Reynold’s Number Locomotion in two-phase biological gels. The gel
is composed of two materials: a viscous fluid solvent phase and a viscoelastic polymer network
phase. A novel Two-phase Immersed Boundary Method (IBM) is developed to simulate the
complicated interactions between an elastic boundary and a mixture of two fluids with very
different physical properties. A further extension of the method is developed for the case
where fluids satisfy partial-slip and free-slip conditions on the elastic boundary. Our major
conclusions are summarized as following: (i) Our numerical scheme is proved to be robust
and efficient. It can successfully simulate the dynamics of elastic swimmers within biological
fluid with wide range of rheological properties (ii) When polymer network satisfies no-slip
conditions on the swimmer, its elasticity always reduces the swimming speed (iii) If the
swimmer is allowed to slip relative to its surrounding fluid media, the swimming speed can
be greatly enhanced (iv) For the swimmer in a two-fluid mixture, the network elasticity can
actually benefit the locomotion if free-slip condition is satisfied.