A new downscaling method for sub-grid turbulence modeling
Abstract. In this study we explore a new way to model sub-grid turbulence using particle systems. The ability of particle systems to model small scale turbulence is evaluated using high resolution numerical simulations. These high-resolution simulations have been performed with the research atmospheric model Meso-NH and averaged at larger scale from which a complete downscaling experience, via a particle system, have been performed. The particle simulations are compared to the high-resolution simulation for the representation of the wind fluctuations and the turbulent kinetic energy. Despite the simplicity of the physical model used to drive the particles, the results show that particle system is able to represent the average field. It is shown that this system is able to reproduce much finer turbulent structures than the numerical high-resolution simulations. In addition, this study provides an estimate of the effective spatial and temporal resolution of the numerical models. This highlights the need for higher resolution simulations to be able to evaluate the very fine turbulent structures predicted by the particle systems. Eventually a study of the influence of the forcing scale on the particle system is presented.