Potential applications of elastic instability and elastic turbulence: A comprehensive review, limitations, and future directions

Abstract

Viscoelastic fluids, a subclass of complex fluids, are employed across various applications, from biological processes to large-scale industrial operations. These fluids exhibit complex flow behaviors resulting from non-linear elastic stresses that arise from the stretching and relaxation of their microstructures, such as polymer molecules in viscoelastic polymer solutions, within a deformed flow field. One notable phenomenon associated with these fluids is purely “elastic instability” (EI), which occurs when elastic stresses interact with the streamline curvature in a flow system at low Reynolds numbers (the ratio of inertial to viscous forces). Specifically, EI manifests when the Weissenberg number (the ratio of the microstructure relaxation time to the rate of flow deformation) surpasses a critical threshold. As the Weissenberg number continues to increase, the unstable flow field resulting from EI further transits to a more chaotic and turbulent-like flow state known as “elastic turbulence” (ET). The fluctuating hydrodynamics characteristics of ET display statistical similarities to conventional Newtonian turbulence observed at high Reynolds numbers. Over the past two decades or so, extensive research has been conducted within the complex fluids research community to explore these two phenomena, resulting in several comprehensive articles that outline the development and understanding of ET. This article focuses on the potential application perspectives of these two phenomena. In particular, this article aims to provide a thorough review of the applications of EI and ET phenomena, particularly in three main areas: microfluidic mixing, microscale heat transfer, and chemically enhanced oil recovery (EOR) processes. Furthermore, this review will also provide a discussion on the limitations and future research directions associated with these two phenomena, highlighting their potential from an application standpoint.