Lagrangian simulation of dispersion in turbulent shear flow with a hybrid computer



Two-dimensional turbulent diffusion is modeled with a generalized Langevin equation. Instantaneous velocities are simulated by using white noise filtered to simulate turbulence. By generating fluctuating signals that are partially correlated, it is possible to model diffusion for a turbulent shear field. The result show that the dispersion is independent of shear for long and short diffusion times but depend strongly on shear for intermediate times.