Enhancement of heat transfer by a buckled flexible filament in a channel flow

The flow-induced snap-through dynamics and heat transfer enhancement of a buckled flexible filament in a channel flow were explored using the penalty immersed boundary method. Two distinct edge configurations were examined for comparison. One edge condition was a simply supported leading edge and a clamped trailing edge (SC); the other condition was two clamped edges (CC). Three modes were identified on the basis of variations in channel height and bending rigidity: an equilibrium mode, a streamwise oscillation mode, and a snapthrough oscillation mode. The buckled filament under snap-through oscillation mode exhibited the best heat transfer enhancement. The vortex shedding mechanism of the snap-through oscillation mode was explored. Enhancement of heat transfer was achieved via the interplay of snap motions and shed vortices. The channel width strongly influenced the heat transfer enhancement, with the effect being diminished in broader channels. Bending rigidity also played a critical role, influencing the filament's motion patterns and thereby affecting the heat transfer performance. The SC cases showed superior heat transfer enhancement compared with the CC cases. The incorporation of the buckled filament, utilizing an optimal parameter set, led to an 18% enhancement in thermal efficiency factor when compared to an open channel configuration. These findings provide valuable insights into the heat transfer enhancement of a buckled flexible filament in a channel flow.