Abstract

Nonlinear acoustic phenomena such as acoustic streaming and the formation of shock waves are theoretically well described in the scientific literature for a particular set of cases. A variety of well-known results give an accurate portrait of the different physical processes associated with nonlinear propagation of acoustic waves. However, when these waves travel along waveguides with different geometries and terminations, the aforementioned processes require a three-dimensional description, and this is often difficult to achieve. For these cases, visualisation methods such as the schlieren technique and numerical simulations offer both confirmation of known results and insight into the interplay between separate processes. Various examples involving mostly narrow ducts will be discussed, with particular emphasis placed on the manner in which qualitative results may be applied to theoretical analysis.