The dynamics of Lagrangian particles and tracers in the vicinity of a baroclinically unstable zonal jet are investigated in a simple 2-layer model with an initially quiescent lower layer. Presence of a wave induces a particle drift which is dominated by a Stokes drift rather then the mean Eulerian velocity due to the wave. Stable and unstable waves both have zonal Stokes drift with a similar me...

The advection equation is the basis for mathematical models of continuum mechanics. In the approximate solution of nonstationary problems it is necessary to inherit main properties of the conservatism and monotonicity of the solution. In this paper, the advection equation is written in the symmetric form, where the advection operator is the half-sum of advection operators in conservative (diver...

systems in which reaction terms are coupled to diffusion and advection transports arise in awide range of chemical engineering applications, physics, biology and environmental. in these cases, thecomponents of the unknown can denote concentrations or population sizes which represent quantities andthey need to remain positive. classical finite difference schemes may produce numerical drawbacks s...

This paper deals with the development of a simple urban model for flow and dispersion in the urban canopy layer (UCL). The flow module of the model calculates spatially-averaged wind profiles adopting a technique recently proposed in the literature, which is based on a balance equation between the obstacle drag force and the local shear stress. Spatially-averaged wind profiles are used as input...

Tracer responses in gas-liquid, two-phase flow through a fractured layer are discussed. Experiments were carried out using a glass bead bed in a cylinder. In the results, over a wide range of flow conditions of particle size, fluids-flow velocity, and water saturation (Sw), one of three types of liquidand gas-flow pattern was obtained: a single-phase (water) flow with entrapped gases, a bubble ...

the accurate estimation of reaeration rate coefficient, because of its effects on dissolved oxygen in rivers, is one of the most important initial steps of water quality management. the main goal of this paper is to evaluate the effects of reaeration rate coefficient on the river water dissolved oxygen, case study dinachal river, iran. to achieve these aims, water quality samples were collected...

Fractional advection–dispersion equations are used in groundwater hydrology to model the transport of passive tracers carried by uid ow in a porous medium. In this paper we develop practical numerical methods to solve one dimensional fractional advection–dispersion equations with variable coe1cients on a 2nite domain. The practical application of these results is illustrated by modeling a radia...

The dispersion of inertial particles continuously emitted from a point source is analytically investigated in the limit of small inertia. Our focus is on the evolution equation of the particle joint probability density function p(x,v, t), x and v being the particle position and velocity, respectively. For finite inertia, position and velocity variables are coupled, with the result that p(x,v, t...

A time-splitting approach for advection–dispersion equations is considered. The dispersive and advective fluxes are split into two separate partial differential equations (PDEs), one containing the dispersive term and the other one the advective term. On triangular elements a triangle-based high resolution Finite Volume (FV) scheme for advection is combined with a Mixed Hybrid Finite Element (M...