Large eddy simulation of dispersion of particles in turbulent jets (Q2770620)

The paper deals with the effects of initial velocity and Stokes number on the dispersion of small particles in turbulent jets. The Stokes number is defined as the quotient between the characteristic time scale of the flow and the characteristic time scale of the particles, and it represents the ability of the particles to follow the fluid flow. In the model, small particles are released in a fluid jet, the only force that acts on the particles is aerodynamic drag. It is assumed that particles are spherical and that the mean distance between the particles is much larger than the diameter of the particles. Moreover, the mean distance between the particles is larger than the smallest resolved scale in the simulation. Finally, the interaction between the particles is neglected due to large distance between the particles. The simulation of the continuous phase (i.e. the fluid) is done with large eddy simulation techniques, and only the space variable is filtered. The individual particles are tracked by Lagrangian method, implemented by Runge-Kutta method. It is observed that the dispersion of the particles depends on initial velocity and on Stokes number, where the initial velocity is strongly determinant for the behaviour of particles with large Stokes number, while it is quickly forgotten by particles with a small Stokes number. In some cases, the numerical results are compared with experimental data.