## Abstract

This study has conducted parallel simulations of interacting inertial particles in statistically-steady isotropic turbulence using a newly-developed efficient parallel simulation code. Flow is computed with a fourth-order finite-difference method and particles are tracked with the Lagrangian method. A binary-based superposition method has been developed and implemented in the code in order to investigate the hydrodynamic interaction among many particles. The code adopts an MPI library for a distributed-memory parallelization and is designed to minimize the MPI communication, which leads to a high parallel performance. The code has been run to obtain collision statistics of a monodisperse system with St=0.4 particles, where St is the Stokes number representing the particle relaxation time relative to the Kolmogorov time. The attained Taylor-microscale based Reynolds number _{R λ} ranges from 54.9 to 527. The largest simulation computed the flow on 2000^{3} grids and 1000^{3} (one billion) particles. Numerical results have shown that the collision kernel increases for _{R λ}<100 then decreases as _{R λ} increases. This Reynolds dependency is attributed to that of the radial distribution function at contact, which measures the contribution of particle clustering to the collision kernel. The results have also shown that the hydrodynamic interaction for St=0.4 particles decreases both the radial relative velocity and radial distribution function at contact, leading the collision efficiency less than unity. The collision efficiency increases from 0.65 to 0.75 as _{R λ} increases for _{R λ}<200 and then saturates.

Original language | English |
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Pages (from-to) | 809-827 |

Number of pages | 19 |

Journal | Journal of Computational Physics |

Volume | 242 |

DOIs | |

Publication status | Published - 2013 Jun 1 |

Externally published | Yes |

## Keywords

- Homogeneous isotropic turbulence
- Hydrodynamic interaction
- Parallel computing
- Particle collision

## ASJC Scopus subject areas

- Numerical Analysis
- Modelling and Simulation
- Physics and Astronomy (miscellaneous)
- General Physics and Astronomy
- Computer Science Applications
- Computational Mathematics
- Applied Mathematics