Acceleration scaling and stochastic dynamics of a fluid particle in turbulence

Fluid-particle acceleration in turbulent flows is related to turbulent kinetic energy and its rate of dissipation into heat. Focusing on the statistics of the fluid-particle acceleration conditioned on both the local dissipation rate and the kinetic energy, it is shown that the acceleration grows exponentially with kinetic energy and presents a power law dependence on the dissipation. Based on these observations, we propose a vectorial stochastic model for the dynamics of a fluid particle giving the essential characteristics of Lagrangian turbulence.