Harnessing flow-induced vibration of a D-section cylinder for convective heat transfer augmentation in laminar channel flow

Flow-induced vibration (FIV) of a D-section cylinder is computationally studied and utilized to augment convective heat transfer in a heated laminar channel flow. An in-house fluid-structure interaction (FSI) solver, based on a sharp-interface immersed boundary method, is employed to solve the flow and thermal fields. In conjunction, a spring-mass system is utilized to solve for the rigid structural dynamics. Using numerical simulations, we highlight that the oscillations of a D-section cylinder are driven by vortex-induced vibration and galloping. It is observed that as the cylinder vibrates, vortices are shed from the apex of the cylinder due to the separating shear layers. These vortices, categorized using shedding patterns, interact with the heated channel walls. This interaction results in disruption of the thermal boundary layer (TBL), thus leading to heat transfer augmentation. The enhancement in thermal performance has been quantified using time and space-averaged Nusselt numbers at the channel walls. It is observed that the oscillation amplitude of the D-section cylinder and the extent of vortex-TBL interaction are crucial for determining heat transfer augmentation. Both symmetric and asymmetric thermal augmentation at the top and bottom channel walls have been reported. Finally, to assess the effectiveness of heat transfer augmentation, the D-section cylinder FIV is compared to other FSI systems operating under similar conditions.