Acoustic wave focusing by non-uniform mean flow in a rectangular duct with viscous walls

作者：Markesteijn Anton P^*; Karabasov Sergey A

来源：International Journal of Aeroacoustics, 2014, 13(1-2): 183-205.

DOI：10.1260/1475-472x.13.1-2.183

The high-frequency acoustic wave focusing by a viscous flow profile and reflective duct walls encasing the flow is considered. For a range of the non-uniform meanflow and duct parameters, the problem of image sources generation upstream of the physical source in a rectangular duct is investigated computationally and analytically. This is done first by solving the Navier-Stokes equations at high Reynolds number in the Eulerian framework, then by using a Lagrangian particle method based on the high-frequency approximation, and finally, with a simple analytical plug-flow-profile model based on geometrical acoustics. It is shown that both the meanflow-refraction and wall-reflection play a key role in the focusing of acoustic waves. The analogy with geometrical acoustics is further emphasized by comparing the Navier-Stokes simulation results with the experimental data from the literature on acoustic wave focusing by a lens made of a negatively refractive material.

• 出版日期2014