Analysis of the influence of incoming flow turbulence on the flow in a supersonic air intake by the RANS/ILES method. Estimation of dissipative properties of the difference scheme by an example of modeling the decay of homogeneous isotropic turbulence in the ILES

Dissipative properties of the difference scheme implemented in the RANS/ILES method are estimated by an example of the problem of the decay of homogeneous isotropic turbulence calculated in the ILES. The effect of scheme settings, time step, and grid cell size on the numerical diffusion level—scheme dissipation in a wide range of turbulent Mach numbers—is studied. The energy spectra for different time instants of the evolution of the modeled flow are constructed, and their physical adequacy in terms of the theory of homogeneous isotropic turbulence and correspondence to experimental data are estimated. A satisfactory coincidence with experimental results and correspondence to the theoretical structure of the spectrum are obtained. A comparison with results of modeling the decay of homogeneous isotropic turbulence in the ANSYS CFX software package with the use of different explicit subgrid models of turbulence is carried out.