A heatsink comprises a base (110, 210, 310), a fin (120, 220, 320) attached to the base, and a piezoelectric patch (130, 230, 330) attached to the fin. The piezoelectric patch causes the fin to oscillate, thus generating air circulation near the fin surface. This airflow disturbs the boundary layer near the fin and dramatically increases the heat transfer from the fin to air compared to a non-oscillating fin, even for the same bulk flow rate.