Systems in which reaction terms are coupled to diffusion and advection transports arise in a wide range of chemical engineering applications, physics, biology and environmental. In these cases, the components of the unknown can denote concentrations or population sizes which represent quantities and they need to remain positive. Classical finite difference schemes may produce numerical drawback...

In most studies of the net ecosystem-atmosphere exchange of CO2 (NEE) using tower-based eddy covariance (EC) systems it has been assumed that advection is negligible. In this study we use a scalar conservation budget method to estimate the contribution of advection to NEE measurements from a very tall tower in northern Wisconsin. We examine data for June–August 1997. Measured NEE0, calculated a...

We have examined some of the characteristics of moisture advection and its relation to precipitation over Australia. Seasonal extremes of moisture advection have changed considerably during the latter part of the 20th century. Analysis of its skewness reveals that the relative occurrence of these events has increased. A kurtosis analysis shows that there has been a geographical shift of where t...

In the stratified ocean, vertical motions arise from both adiabatic and diabatic mechanisms. Diapycnal advection is the vertical component of flow across an isopycnal surface which occurs when mixing produces a divergent flux of buoyancy. Buoyancy forcing of the lateral flow by vortex stretching occurs when diapycnal advection rates vary with depth. Microstructure observations of enhanced turbu...

Advection has been the standard transport mechanism in flow visualization. Diffusion, in contrast, has not been considered important in visual flow field analysis so far, although it is inherent to many physical processes. We present a novel technique that allows for interactive 3D visualization of both advection and diffusion in unsteady fluid flow. We extend texture-based flow visualization, ...

water quality prediction is a valuable tool for pollutant control in aquatic environments. a river system is selected and one-dimensional flow is assumed for the simulation of pollutant transport in this paper. advective and diffusive terms of transport equation are considered separately. different functions of advective transport are proposed and applied for a specified velocity on the discret...

prediction of spatial and temporal variation of water quality is vital for managing pollutantsdisposal into the rivers. depletion of dissolved oxygen (do) takes place due to the consumption of oxygen bymicrobes to digest bio-degradable pollutants which enter a water course. reaeration takes place in a specificrate depending on do deficit. many investigators have formulated models as an alternat...

Stream surfaces are a classic flow visualization technique used to portray the characteristics of vector fields, and texture advection research has made rapid advances in recent years. We present a novel hybrid visualization of texture advection on stream surfaces. This approach conveys properties of the vector field that stream surfaces alone cannot. We apply the visualization technique to var...

We present a new method for the realistic real-time simulation of rivers. Our solution includes a 2D fluid solver that simulates the flow of a river’s surface, an efficient method for adaptively computing 3D flow information and an animated 3D procedural wave texture that is advected through the fluid via advection particles in order to mimic the highly detailed fluid surfaces that are characte...