Core Concepts
The authors propose and analyze robust and structure-preserving time discretization and linearization schemes for solving degenerate and singular evolution systems arising in models for biofilm growth and other applications. The schemes are shown to be well-posed, preserve positivity and boundedness of the solutions, and converge unconditionally.
Abstract
The content presents a numerical analysis of a class of degenerate quasilinear parabolic systems that arise in modeling biofilm growth and other applications. The key points are:
-
Motivation and background:
- The system consists of a degenerate parabolic equation coupled with either a parabolic or an ODE equation, exhibiting degenerate and singular diffusion.
- Such systems appear in modeling biofilm growth, porous medium flow, wildfire spreading, and other applications.
-
Time discretization:
- A semi-implicit time discretization scheme is proposed that decouples the equations, allowing for efficient sequential solution.
- The time-discrete solutions are shown to be well-posed, positive, bounded, and converge to the time-continuous solutions as the time step goes to zero.
-
Linearization:
- For the nonlinear time-discrete problems, two iterative linearization schemes are introduced: the L-scheme and the M-scheme.
- The L-scheme is shown to converge unconditionally, while the M-scheme achieves a faster convergence rate in the non-degenerate case.
- The convergence of the linearization schemes is proven to be independent of the spatial discretization.
-
Numerical results:
- Finite element discretization is employed, and the performance of the proposed schemes is compared to other commonly used schemes.
- The results confirm the robustness and efficiency of the proposed time discretization and linearization approaches.