Rheological modeling with GENERIC and with the Onsager principle

TL;DR

This paper compares three theoretical frameworks—conservation laws, GENERIC, and Onsager principle—for modeling complex fluid flows, specifically applied to isothermal, incompressible polymeric fluids, highlighting their differences and similarities.

Contribution

It provides a comparative analysis of three distinct modeling frameworks for complex fluids, emphasizing their theoretical foundations and applicability to polymeric fluids.

Findings

GENERIC effectively captures thermodynamic consistency.

Onsager principle offers minimal resistance modeling.

Conservation laws serve as a fundamental baseline.

Abstract

In this paper we compare three frameworks for modeling flows of complex fluids: (i) local conservations of mass, momentum and energy, (ii) GENERIC, and (iii) Onsager principle. The first is based on the mass, momentum, and energy conservation implied by mechanics, the second on the observed approach of externally unforced fluids to equilibrium states at which their behavior is well described by equilibrium thermodynamics, and the third on the minimal resistance to external influences. The comparison is illustrated on isothermal and incompressible polymeric fluids.