The effect of estuarine circulation and tidal trapping on mixing in the Hudson Estuary is investigated by a numerical model simulation of a tracer release. The data set used in this study was obtained from a large-scale SF6 tracer release experiment conducted during July/August 2001. It consists of over 2,000 measurements taken over a period of two weeks and distance of 110 km with a typical re...

BACKGROUND Many animals must locate odorant point sources during key behaviors such as reproduction, foraging and habitat selection. Cues from such sources are typically distributed as air- or water-borne chemical plumes, characterized by high intermittency due to environmental turbulence and episodically rapid changes in position and orientation during wind or current shifts. Well-known exampl...

In this study, 2D simulations of xenon plasma plume flow fields from a D55 anode layer Hall thruster are performed with a hybrid particle-fluid method. In this simulation, the Boltzmann model and a detailed fluid model are used to compute the electron properties, the direct simulation Monte Carlo method models the collisions of heavy particles, and the Particle In Cell method models the transpo...

In secondary steelmaking, the refining operation is typically carried out in a metallurgical ladle that is commonly furnished with gas injection facilities. Since gas injection plays an intrinsic role in determining the efficiency of secondary steelmaking and thus the quality of final products, a great volume of work has been conducted mostly utilizing air-water systems at room temperature. Des...

Turbulent plumes, which are seen in a wide number of industrial and natural flows, have been extensively studied; however, very little attention has been paid to plumes which have an internal mechanism for changing buoyancy. Such plumes arise in e.g. industrial chimneys, where species can react and change the density of the plume material. These plumes with chemical reaction are the focus of th...

A breathing sphere model is developed for molecular dynamics simulations of laser ablation and desorption of organic solids. An approximate representation of the internal molecular motion permits a significant expansion of the time and length scales of the model and still allows one to reproduce a realistic rate of the vibrational relaxation of excited molecules. We find that the model provides...

E mergency response deals with the reaction to a natural or man-made disaster and involves containing the disaster situation. The process is time-critical because many lives depend on how quickly and accurately emergency responders make decisions. During an emergency response, emergency operations centers (EOCs) face different problems depending on the category the emergency falls under (fire, ...

To explain the formation of surface features on Europa, Enceladus, and other satellites, many authors have postulated the spatial localization of tidal heating within convective plumes. However, the concept that enhanced tidal heating can occur within a convective plume has not been rigorously tested. Most models of this phenomenon adopt a tidal heating with a temperature-dependence derived for...

[1] In this research, we investigate the large-time solution behavior of a representative bioreactive transport model under the conditions that the mixing of two required substrates occurs only in the directions transverse to groundwater flow. The transport physics is governed by the commonly used advection-dispersion equations at a steady uniform flow field. The microbial population dynamics a...

We present simultaneous two-dimensional velocity and scalar concentrations measured on a central vertical plane in a turbulent plume. We use an edge-detection algorithm to determine the scalar plume edge, and compare the data obtained in both a fixed Eulerian frame and relative to local plume coordinates defined in terms of the instantaneous plume edge. We observe that the time-averaged distrib...