Enhancement of heat transfer by flexible vortex generators with inclination angle

Heat transfer is an important aspect to consider when designing systems in various industries, and many researchers have introduced vortex generators to improve the heat transfer. In the case of a rigid vortex generator, energy loss is generated owing to a high pressure drop. In recent years, numerous studies have been conducted to improve heat transfer using a flexible vortex generator. In this study, an asymmetric inclined flexible flag was adopted as the vortex generator and an immersed boundary method was used to consider the fluid-flexible body interaction. When the bending rigidity of the flexible vortex generator was constant, the fluttering motion of the vortex generator increased as the inclination angle increased, and vortex structures were produced by the fluttering motion, thereby increasing the heat transfer. When the inclination angles were 45° and 135°, the heat transfer was observed to be increased by 2% and 116%, respectively.