Abstract
This study investigated the role of fin flexibility to control the fluid flow on natural convection heat transfer within a square cavity containing a heated triangular block. Two flexible fins, attached to the cavity’s cold vertical walls, interact with an incompressible fluid under varying Rayleigh numbers (Ra) and elasticity modulus (Et), highlighting how these parameters affect thermal and fluid dynamics and the interaction between the top and the bottom regions of the cavity. The novelty of this study is to create passive control over the flexible fins to control the fluid flow and creating a separation between the top region or the bottom region using these mentioned parameters. Using the Arbitrary Lagrangian-Eulerian (ALE) technique, the fluid-structure interaction (FSI) model captured the bending response of the fins and the resulting convective heat transfer. Results indicated that lower fin rigidity (low Et) significantly enhanced thermal mixing and heat transfer due to increased fluid flow, driven by the bending of the fins at higher Ra. Hence, the top and the bottom regions of the cavity interacted with each other. Conversely, higher Et values restricted fluid circulation, maintaining thermal stratification and reducing heat transfer efficiency and separated these regions. This study provides insights into controlling and optimizing heat transfer in systems with flexible structures, with potential applications in thermal management and energy-efficient design.