Computational investigation of acoustic streaming in a two‐dimensional duct

The present work investigates the nonlinear phenomenon of Rayleigh streaming characterized by acoustically driven flows attenuated by wall friction, resulting in nonzero average streaming velocities and circulation zones within the duct. A two‐dimensional, long and narrow duct is considered in the present study with one end closed and the other subject to a sinusoidal acoustic velocity of varying frequency and amplitude, leading to a standing wave within the duct. A computational fluid dynamics code is used to solve the unsteady, compressible Navier–Stokes equations in two dimensions with turbulence modeling. Since the formation of streaming depends on the velocity profile within the Stokes layer, a high resolution grid is employed near the walls. The effect of inlet conditions is examined in terms of the circulation patterns, including the number of zones per wavelength and penetration depth into the fluid, as well as the mean velocity profiles.