It is shown for a flow field with vorticity, that even if the velocity
u is axisymmetric, the term [(del X u) . del)]u is, in general, nonze
ro. In his treatment of acoustic streaming near a rigid sphere, Lane [
J. Acoust. Soc. Am. 27, 1082 (1955)] dropped this term; this is probab
ly why his results differ from those of others.