Capturing volume fraction effects on turbophoresis with a reduced number of computational particles

In turbulent particle-laden flows, turbophoresis leads to enhanced particle concentrations near solid boundaries. However, particle-particle collisions have been shown to significantly attenuate this effect, even at rather low volume fractions. As a result, Lagrangian-Eulerian simulations of wall-bounded particle-laden flows can be very sensitive to the number of Lagrangian particles simulated. In this talk, we explore a method for reducing the number of computational particles below the physical number while maintaining an accurate representation of collisional effects on the near-wall concentration profile. This is done by artificially increasing the size of the particles used for computing particle-particle collisions while leaving the size unaltered for other parts of the computation such as the drag law and particle-wall collisions. Both high and low Stokes number regimes are considered. The results are promising for reducing the cost of Lagrangian-Eulerian simulations of turbulent wall-bounded flows.