Turbophoresis and preferential accumulation of inertial particles in compressible turbulent channel flow: Effect of Mach number

This paper investigates the effects of the Mach number on turbophoresis and the preferential accumulation of particles. A particle relaxation time weighting transformation is proposed which collapses the concentration profiles not only for particles with small inertia, but also for turbulence with various compressibility at the studied low Reynolds number and in the inner region. Inertial particles in compressible wall turbulence tend to distribute in high-fluid-density and negative-fluid-dilatation regions. This is explained by the changes in turbulent structures at varying Mach number, which in turn also account for the varying scales of particle streaks.