Numerical study of heat transfer enhancement and fluid flow behavior in fluid-structure interaction within a channel equipped with flexible oscillating walls

The present study investigates the cooling of a heated rectangular plate through fluid flow in a channel, utilizing the interaction between solid and fluid with two elastic walls under oscillating conditions and external forces. The incompressible fluid flow passes through a two-dimensional channel containing a constant heat flux heat source in the center, with two identical and equally sized elastic walls positioned at the top and bottom of the channel. As the fluid flows over the heated surface and the elastic walls oscillate, the rate of heat transfer to the fluid changes. In this scenario, the heat exchange rate behaves as a function of the conditions of the oscillating elastic surfaces, the magnitude of the force applied to the elastic walls, and the oscillation period of the applied force. The goal of the simulations conducted is to examine the application of replacing the elastic boundary with a rigid boundary in part of the channel and the impact of oscillation period and force magnitude. In this study, laminar flow with four different Reynolds numbers (600, 1100, 1600, and 2100) and three different applied force amplitudes (200, 400, and 800 N/m) alongside four oscillation periods (0.5, 0.25, 0.125, and 0.07 seconds) has been analyzed After solving the governing equations, including the energy equation, momentum equations, and elastic surface equations, utilizing the arbitrary Eulerian-Lagrangian method in COMSOL engineering software, the results indicate that decreasing the oscillation period enhances fluid flow mixing, thereby increasing the heat transfer rate to its optimal level. The findings show that a continuous reduction of the applied force’s oscillation period to an optimal level can be effective; conversely, exceeding this optimal point can negatively impact the heat dissipation rate. The highest percentage increase in the convective heat transfer coefficient, compared to the rigid channel, at a constant applied force of 800 N/m for Reynolds numbers 600, 1100, 1600, and 2100 were 301%, 297%, 341%, and 328%, respectively.