Fig. 2.

Comparisons of boundary conditions between the two numerical methods on the modelling of classical boundary-driven streaming fields in 2D rectangular channels: a the Reynolds stress method (RSM) and b the limiting velocity method (LVM), where ${\mathit{\sigma }}_0$ is the amplitude of harmonic oscillation, $f$ is its driving frequency, the orange layer is the acoustic boundary layer thickness (${\mathit{\delta }}_v$, not to scale) and $u_L$ is the limiting velocity working as a slip velocity boundary condition on the edge where the acoustic boundary layer is ignored (colour figure online)