Fluid-Structure Interaction and Heat Transfer Characteristics of a Thin Flexible Heater Submersed in Non-Newtonian Fluids Inside a Shear-Driven Cavity

Abstract

This study examines fluid-structure interaction (FSI)–induced flow and heat transfer phenomena in a double-sided shear-driven, that is, lid-driven cavity filled with non-Newtonian power-law fluids. A flexible thin heater positioned at the center of the cavity serves as the heat source, while the moving side walls maintained at constant low temperature perform as a heat sink. The numerical approach adopts the finite element Galerkin method, integrating the Arbitrary Lagrangian–Eulerian framework with moving mesh technique to solve the associated flow, thermal, and stress fields. The thermoelastodynamic system behavior is analyzed through streamline, isothermal, and heater deformation visualizations, along with an evaluation of heat transfer performance, namely, the average Nusselt number. FSI-induced internal stress scenario in the heater is also studied in terms of maximum von Mises stress. Variation of system conditions necessarily includes mixed convection strength, shearing effect, fluid rheology, and flexibility of the heater manifested by four governing system parameters, namely, the Richardson number (0.1 ≤ Ri ≤ 10), Reynolds number (100 ≤ Re ≤ 300), power-law index (0.6 ≤ n ≤ 1.4), and Cauchy number (10⁻⁴ ≤ Ca ≤ 10⁻⁸). The findings of this study reveal a significant improvement in heat transfer for shear-thinning fluids, with the most notable enhancement occurring at the highest Richardson number (Ri), where the heat transfer rate shows an increase of up to 33.33% compared with Newtonian fluids. The insights of this study might be helpful in heat transfer enhancement of industrial process equipment, particularly in applications such as food processing, electronics cooling, and chemical engineering, where non-Newtonian fluids are extensively used in reactors and related thermofluid systems.