Compressible turbulent channel flow with impedance boundary conditions

We have performed large-eddy simulations of isothermal-wall compressible turbulent channel flow with linear acoustic impedance boundary conditions (IBCs) for the wall-normal velocity component and no-slip conditions for the tangential velocity components. Three bulk Mach numbers, Mb = 0.05, 0.2, 0.5, with a fixed bulk Reynolds number, Reb = 6900, have been investigated. For each Mb, nine different combinations of IBC settings were tested, in addition to a reference case with impermeable walls, resulting in a total of 30 simulations. The adopted numerical coupling strategy allows for a spatially and temporally consistent imposition of physically realizable IBCs in a fully explicit compressible Navier-Stokes solver. The IBCs are formulated in the time domain according to Fung and Ju [“Time-domain impedance boundary conditions for computational acoustics and aeroacoustics,” Int. J. Comput. Fluid Dyn. 18(6), 503–511 (2004)]. The impedance adopted is a three-parameter damped Helmholtz oscillator with resonant ...