Prediction of the efficiency of acoustic damping cavities

In this paper, we first recall the classical results for the laminar dissipation of acoustic energy in the boundary layer of a forced resonator. We then show how this result can be used in conjunction with a Helmholtz solver to calculate the laminar damping of a cavity of arbitrary geometry. This approach is validated by unsteady numerical simulations in both simple and complex geometries. The examples are nonreacting, but the approach can easily be extended to accommodate strong temperature variations. Finally, we suggest and validate a strategy that can use the damping obtained from the Helmholtz solver to calculate an equivalent resistive boundary condition that can be used in unsteady-time-domain simulations.