Error induced by neglecting subgrid chemical segregation due to inefficient turbulent mixing in regional chemical-transport models in urban environments

Subgrid models in turbulent mixing

We are concerned with the chaotic flow fields of turbulent mixing. Chaotic flow is found in an extreme form in multiply shocked Richtmyer-Meshkov unstable flows. The goal of a converged simulation for this problem is to obtain converged solutions for such micro solution features as the joint probability distributions of the temperature and species concentration, as well as the macro features su...

Subgrid models for mass and thermal diffusion in turbulent mixing∗

Dynamic Models for Subgrid-scale Transport and Mixing of Reactants in Atmospheric Turbulent Reacting Flows

Large-eddy simulation (LES) can provide valuable highresolution spatial and temporal information required to study the effects of turbulent transport and mixing on the chemical transformation of reacting scalars in the atmospheric boundary layer (ABL). LES consists of explicitly resolving all scales of turbulent transport larger than the grid scale (on the order of tens of meters in the ABL), w...

Data Assimilation in Multiscale Chemical Transport Models

In this paper we discuss variational data assimilation using the STEM atmospheric Chemical Transport Model. STEM is a multiscale model and can perform air quality simulations and predictions over spatial and temporal scales of different orders of magnitude. To improve the accuracy of model predictions we construct a dynamic data driven application system (DDDAS) by integrating data assimilation...

Chemical element transport in stellar evolution models

Stellar evolution computations provide the foundation of several methods applied to study the evolutionary properties of stars and stellar populations, both Galactic and extragalactic. The accuracy of the results obtained with these techniques is linked to the accuracy of the stellar models, and in this context the correct treatment of the transport of chemical elements is crucial. Unfortunatel...