Acoustic streaming

In recent years, the need for accurate analysis of acoustic streaming has become urgent, as classical methods fail to quantify flows generated by acoustic waves beyond a few hundred kHz. This problem, identified since Lighthill’s seminal 1978 namesake publication, remains unresolved. Researchers, including myself, have relied on computational analysis and approximations to address some of these challenges. Few have examined the dynamic behavior of acoustic streaming—such as delayed onset, response to inharmonic excitation, and flows sustained after the acoustic wave stops—despite their importance in experiments. The difficulty lies in analyzing these flows. However, after extensive work on an alternative approach, we now have a method for closed-form analysis of one-dimensional acoustic streaming that includes transient behavior and accounts for nonlinear compressibility and viscous effects. We offer a coherent and straightforward plan for analyzing simple acoustic streaming cases where classical theories fail. This method can model both steady-state and transient acoustic streaming, potentially eliminating the need for computational analysis and providing enough physical insight for design purposes. Our goal is to equip listeners with the tools to perform this analysis themselves without need for tedious computational methods.