A hybrid approach for simulating turbulent collisions of hydrodynamically-interacting particles

A hybrid direct numerical simulation (DNS) approach is proposed for simulating turbulent collisions of hydrodynamically-interacting particles, under the assumptions that the disturbance flows due to particles are very localized in space and there is a sufficient length-scale separation between the particle size and the Kolmogorov scale of the undisturbed turbulent flow. The approach consists of direct simulation of the undisturbed turbulent flow and an analytical representation of local small-scale disturbance flows induced by the particles. This hybrid DNS approach provides, for the first time, a quantitative research tool to study the combined effects of turbulence and hydrodynamic interactions on the motion and collisional interactions of small particles. Several numerical implementation issues are discussed, along with consistency and accuracy of the approach. Areas for further development of the approach are indicated.