Overcoming the hyposonic limit of the compressible Navier-Stokes equations in turbulent flow simulations

Accuracy limitations in solving the compressible Navier-Stokes equations at low speed/Mach numbers have drawn research interest for many decades. Despite numerous attempts to overcome these limitations, a comprehensive solution remains elusive, particularly regarding turbulent flows. This study introduces an innovative numerical approach called the Numerical Enhancement for Hyposonic Accuracy, aimed at effectively addressing the challenges of solving the compressible Navier-Stokes equations in turbulent boundary layer flows within the hyposonic limit. The new method locally adjusts the reconstructed flow velocity, significantly reducing the dissipation of low Mach number features while imposing minimal additional computational cost and enabling straightforward implementation. The effectiveness of the proposed method is validated through implicit large eddy simulations of weakly compressible turbulent channel flow. This validation includes detailed evaluations of the friction Reynolds number, streamwise velocity profiles, and higher-order turbulence statistics. The analysis conclusively demonstrates that the proposed method significantly reduces numerical dissipation in subsonic turbulent boundary layers while preventing the emergence of any artificial noise in numerical simulations at the hyposonic limit.