Compressibility effects in turbulent channel with weak spanwise rotation using direct numerical simulations

Direct numerical simulations of temporally evolving turbulent channel flows with a weak spanwise rotation are conducted at a rotation number of 0.05 and Mach numbers of 0.3, 1.5, and 3.0 to investigate the influence of compressibility effects on turbulent statistics and large-scale structures. The corresponding Reynolds numbers are 2820, 3000, and 4880. Investigation shows that many asymmetric characteristics for incompressible flow also hold for compressible flow. The mean and fluctuating turbulent statistics distributions are similar to those for incompressible flows and shift from the suction side toward the pressure side. Weak spanwise rotation alters the mean the Mach number. The recovery enthalpy collapses between the pressure and suction sides and is independent of the Mach number. The Reynolds shear stress distributions are similar for compressible flows but with larger slopes than incompressible flows. When introducing semi-local scaling, the turbulent kinetic energy budget at pressure side is insensitive to compressibility effects. The average spanwise spacing of near-wall streaks increases as with the Mach number. The number of Taylor-Gortler vortex pairs is determined primarily by the aspect ratio of the computational domain, and is independent of the compressibility effects.

Automated summary

This study conducts direct numerical simulations to investigate the influence of compressibility effects on turbulent statistics and large-scale structures in temporally evolving turbulent channel flows with a weak spanwise rotation. The results show that compressibility has some impact on the turbulent statistics distributions, but many asymmetric characteristics still exist.