Comment on Papers Concerning Rectified Diffusion of Cavitation Bubbles

It is shown that the threshold of rectified diffusion according to the Hsieh and Plesset solution is in fact frequency dependent when the inertial terms in the equation of motion of the bubble are not neglected. A comparison is made between the threshold calculated from the modified Hsieh and Plesset solution and that obtained by Eller and Flynn, using numerically computed radius‐time curves.