Development of flow characterization system using ultrasonic methods

This article deals with the radiation of sound from ultrasonic transducers located on a flat surface and bounding a shear flow. The aim of the experiments is to measure time delays between flushed transducers in order to characterize flow velocity. Considering that the sound has an infinitely small wavelength, comparison between numerical (simulated using Matlab) and experimental results shows that sound radiation can be described by a ray theory of acoustic propagation. The presence of a turbulent boundary layer creates curved paths of propagation. This phenomenon combined with the angle of transducers towards the flow stream affects measurements of the experiments. At high angles, the propagation of sound can be compared with a direct transmission between the transducers.