The connection between anomalous scaling of structure functions (intermittency) and numerical methods for turbulence simulations is discussed. It is argued that the computational work for direct numerical simulations (DNS) of fully developed turbulence increases as Re4, and not as Re3 expected from Kolmogorov’s theory, where Re is a large-scale Reynolds number. Various relations for the moments...

A dissipative scale-similarity subgrid model was recently proposed in which only the dissipative part of the subgrid stresses was added to the momentum equations. This was achieved by adding the gradient of a subgrid stress only when its sign agreed with that of the corresponding viscous term. In the present work, this idea is used the other way around as forcing in hybrid large eddy simulation...

In this work, a novel model for Large Eddy Simulations (LES) of high Reynolds moderate Damkohler number turbulent §ames is proposed. The development is motivated by the need for more accurate and versatile LES combustion models for engineering applications such as jet engines. The model is based on the ¦nite rate chemistry approach in which the ¦ltered species equations of a reduced reaction m...

Atmospheric processes and the associated transport and dispersion of atmospheric pollutants are known to be highly variable in time and space. Current air-quality models that characterize atmospheric chemistry effects, for example, the Community Multiscale Air Quality model (CMAQ), provide volume-averaged concentration values for each grid cell in the modeling domain given the stated conditions...

A computationally-effective framework is presented that addresses the contribution of subgrid-scale vertical velocity variations in predictions of cloud droplet number concentration (CDNC) in large-scale models. Central to the framework is the concept of a “characteristic updraft velocity”, w, which yields CDNC value representative of integration over a probability density function (PDF) of upd...

Precipitation exhibits significant spatial variability at scales much smaller than the typical size of climate model grid cells. Neglecting such subgrid-scale variability in climate models causes unrealistic representation of land–atmosphere flux exchanges. It is especially problematic over densely vegetated land. This paper addresses this issue by incorporating satellite-based precipitation ob...