Three-dimensional numerical study of acoustic streaming phenomenon in rectangular resonator

The article presents a three-dimensional numerical study of the large-amplitude, acoustically driven streaming flow in rectangular resonator for different frequencies of the acoustic wave and different temperature regime, isothermal and 60 K temperature difference between the top and bottom walls. The utilized numerical model was based on the Navier-Stokes compressible equations, the ideal gas model, and finite volume discretization. The oscillating wall of the resonator was modeled as a dynamically moving boundary of the numerical domain. The size of the resonators was adjusted to fit one period of the acoustic wave. The research revealed a stationary pair of streaming vortices in the resonator with a characteristic three-dimensional structure. Their intensity was much greater in the case of nonisothermal flow. The study of the impact of side walls on the intensity of streaming revealed its gradual decrease with approaching the walls, creating a quasiparabolic profile in the resonator. Interestingly, the relationship between the intensity of streaming and the frequency of the acoustic wave turned out to be not trivial and two maxima for different frequencies could be observed.