Ultrasound scattering by a vortical flow

✍ Scribed by A.C. Martı́; S. Varela; A.C. Sicardi-Schifino; C. Negreira

• Publisher: Elsevier Science
• Year: 2003
• Tongue: English
• Weight: 137 KB
• Volume: 327
• Category: Article
• ISSN: 0378-4371
• DOI: 10.1016/s0378-4371(03)00435-7

✦ Synopsis

We report a theoretical and experimental study of the scattering of an ultrasonic wave by a vortical ow. The ow consists of a completely ÿlled cylinder driven by the constant rotation of the two end walls. The angular momentum generated by the disk rotation is concentrated in a strong axial vortex. The scattering of an incident ultrasonic wave allow us to obtain information about the ow. The frequency of the incident wave is assumed to be high in comparison with typical frequencies of the ow. An integro-di erential equation is obtained from the full Navier-Stokes equations describing the interaction of the ow and the ultrasonic wave. Using the Born approximation we obtain a wave equation with source which can be numerically integrated or, in some particular cases, be analytically solved. We numerically identify the regions of the vortical ow that contribute most to the scattered wave. The dependence of the scattered pressure on the scattering angle is also studied. Finally, we compare the numerical results with experimental data.