A second-order accurate, original energy dissipative numerical scheme for chemotaxis and its convergence analysis

TL;DR

This paper introduces a novel second-order accurate numerical scheme for chemotaxis models that preserves positivity and the original energy dissipation, with proven convergence and robust numerical validation.

Contribution

It presents the first second-order scheme that maintains both positivity and original energy dissipation for chemotaxis equations, with rigorous convergence analysis.

Findings

Scheme preserves positivity and energy dissipation in simulations.

Achieves optimal convergence rate with theoretical guarantees.

Demonstrates robustness in blowup simulation scenarios.

Abstract

This paper proposes a second-order accurate numerical scheme for the Patlak-Keller-Segel system with various mobilities for the description of chemotaxis. Formulated in a variational structure, the entropy part is novelly discretized by a modified Crank-Nicolson approach so that the solution to the proposed nonlinear scheme corresponds to a minimizer of a convex functional. A careful theoretical analysis reveals that the unique solvability and positivity-preserving property could be theoretically justified. More importantly, such a second order numerical scheme is able to preserve the dissipative property of the original energy functional, instead of a modified one. To the best of our knowledge, the proposed scheme is the first second-order accurate one in literature that could achieve both the numerical positivity and original energy dissipation. In addition, an optimal rate convergence estimate is provided for the proposed scheme, in which rough and refined error estimate techniques have to be included to accomplish such an analysis. Ample numerical results are presented to demonstrate robust performance of the proposed scheme in preserving positivity and original energy dissipation in blowup simulations.