Beris-Edwards Models on Evolving Surfaces: A Lagrange-D'Alembert Approach

TL;DR

This paper develops thermodynamically consistent surface Beris-Edwards models using the Lagrange-D'Alembert principle, coupling surface flow with nematic order and surface geometry, with potential biological applications.

Contribution

It introduces new surface Beris-Edwards models that incorporate surface flow, nematic order, and geometric constraints within a thermodynamic framework.

Findings

Different formulations of surface Q-tensor dynamics are derived.

Models are related to established simplified models.

Numerical comparisons of formulations are provided.

Abstract

Using the Lagrange-D'Alembert principle we develop thermodynamically consistent surface Beris-Edwards models. These models couple viscous inextensible surface flow with a Landau-de Gennes-Helfrich energy and consider the simultaneous relaxation of the surface Q-tensor field and the surface, by taking hydrodynamics of the surface into account. We consider different formulations, a general model with three-dimensional surface Q-tensor dynamics and possible constraints incorporated by Lagrange multipliers and a surface conforming model with tangential anchoring of the surface Q-tensor field and possible additional constraints. In addition to different treatments of the surface Q-tensor, which introduces different coupling mechanisms with the geometric properties of the surface, we also consider different time derivatives to account for different physical interpretations of surface nematics. We relate the derived models to established models in simplified situations, compare the different formulations with respect to numerical realizations and mention potential applications in biology.