Time adaptive numerical solution of a highly degenerate diffusion-reaction biofilm model based on regularisation
For researchers simulating biofilm dynamics, this method enables more efficient and accurate time integration of degenerate PDEs, addressing a known bottleneck in numerical simulation.
The paper introduces a time-adaptive numerical method for a degenerate diffusion-reaction biofilm model, overcoming the fixed time-step limitation of existing methods. It demonstrates the approach on quorum sensing induction, showing improved efficiency and accuracy.
We consider a quasilinear degenerate diffusion-reaction system that describes biofilm formation. The model exhibits two non-linear effects: a power law degeneracy as one of the dependent variables vanishes and a super diffusion singularity as it approaches unity. Biologically relevant solutions are characterized by a moving interface and gradient blow-up there. Discretisation of the PDE in space by a standard Finite Volume scheme leads to a singular system of ordinary differential equations. We show that regularisation of this system allows the application of error controlled adaptive integration techniques to solve the underlying PDE. This overcomes the major limitation of existing methods for this type of problem which work with fixed time-steps. We apply the resulting numerical method to study the effect of signal diffusion in the aqueous phase on quorum sensing induction in a biofilm colony.