[1] Fossil fuel combustion accounts for >50% of the global atmospheric emission of NOx, but this source is concentrated in the polluted continental boundary layer (CBL) and only a small fraction is exported as NOy (NOx and its oxidation products) to the global troposphere. Better quantification of this export efficiency is needed because of its implications for global tropospheric ozone. A rece...

The long term goal of this project is to advance the state of the art in mathematical methods for detecting key Lagrangian transport structures in velocity field data sets for spatially complex, timedependent, ocean surface flows. Such transport structures are typically not inherently obvious in snapshots of the Eulerian velocity field and require analysis methods with foundations in Lagrangian...

Correctly predicting transient particle transport in indoor environments is crucial to improving the design of ventilation systems and reducing the risk of acquiring airborne infectious diseases. Recently, a new model was developed on the basis of Markov chain frame for quickly predicting transient particle transport indoors. To evaluate this Markov chain model, this study compared it with the ...

A macroscopic traffic flow model describes the evolution of aggregated traffic characteristics over time and space, which is a basic and critical component for various modern intelligent transportation systems, e.g., a real-time freeway control system. Traditional macroscopic traffic flow models are built in the Eulerian coordinates using Eulerian traffic characteristics, such as density, speed...

We formulate a perturbative approximation to gravitational instability, based on Lagrangian hydrodynamics in Newtonian cosmology. We take account of ‘pressure’ effect of fluid, which is kinematically caused by velocity dispersion, to aim hydrodynamical description beyond shell crossing. Master equations in the Lagrangian description are derived and solved perturbatively up to second order. Then...

The goal of this paper is to investigate jump conditions for unsteady small perturbations at impermeable interfaces, slip or bonded, plane or not, between fluids and structures in the presence of initial flow and prestress. Based on conservative equations obtained from a mixed Eulerian-Lagrangian description, interface conditions are first derived in an elegant and straightforward manner thanks...

The spatial dependence of Lagrangian displacement and velocity statistics is studied in the context of a data assimilating numerical model of the Gulf Mexico. In the active eddy region of the Western Gulf, a combination of Eulerian and Lagrangian measures are used to locate strongly hyperbolic regions of the flow. The statistics of the velocity field sampled by sets of drifters launched specifi...

We propose and study parallel numerical algorithms for simulation of flows with elastic membranes, such as red blood cells. The challenges of modeling such flows include accurately resolving the interface motion and enforcing the appropriate interface mechanics. We propose a phase field Eulerian method for implicitly capturing the location of the dynamic interface between two fluids. In additio...