In gas media, the main challenge of the application of ultrasound
is attaining an efficient transmission of the acoustic waves
at high frequencies due to the acoustic impedance mismatch between
transducers and gas as well as the high ultrasonic attenuation
in gas media. However, when ultrasound is applied in an
efficient way, it can produce intense effects on the interfaces, such
as pressure variations or microstirring, which can affect the mass
transfer phenomena (Cárcel et al., 2007a) by reducing the boundary
layer thickness.