Heat dissipation from a heated square cylinder in an oscillating channel flow

Experiments have been performed to investigate heat dissipation from a heated square cylinder in a channel by oscillating flow. During the experiments, the input power and oscillating amplitude (A) are fixed. The effects of the Reynolds number based on the mean flow velocity (Re = 350 and 540) and the oscillating frequency (0 Hz < f _p < 60 Hz) on the heat transfer enhancement are examined. The time-averaged Nusselt number and the Strouhal number were determined for each oscillating condition. The measured Strouhal numbers according to the Reynolds number are compared with the previous results and good agreement is found. The occurrence of the "lock-on" phenomenon is demonstrated for a square cylinder. When the pulsating frequency is in the lock-on regime (f_p ~ 2f_so), the heat transfer from a square cylinder is dramatically enhanced. The heat transfer enhancement is pronounced as the Reynolds number increases