Direct Numerical Simulation of a Free Particle-Laden Round Jet with Point-Particles: Turbulence Modulation

Direct numerical simulation method is used to investigate the small scale ( d p < η/10) turbulence modulation for a spatially evolving free round jet. Because the turbulence modulation phenomena can not be accurately measured by experimental method, the turbulence modulations are poorly understood. The particle diameter in our simulation is smaller than the Kolmogorov length scale η ( d p < η/10), and the point force method can be accurately used for the research of small scale turbulence modulation based strictly on the theory of point force method. The simulation uses an explicit coupling scheme between particles and the fluid, which considers two-way coupling between the particle and the fluid. The DNS results are compared with experimental data with equal Reynolds number (Re = 1700). The particles modulation on the fluid turbulence properties and coherent vortex structures are quantitatively given in our paper, and some new findings on the particles modulation are explicitly explained in this paper, which will further refine our understanding of intricate mechanism of small scale ( d p < η/10) turbulence modulation for a spatially evolving free round jet.