Explore the nature of density-stratified flow over and around topography, including applications to the flow of the atmosphere and ocean.

The dynamics of flows in density-stratified fluids has been and remains now an important topic for scientific enquiry. Such flows arise in many contexts, ranging from industrial settings to the oceanic and atmospheric environments. It is the latter topic which is the focus of this book. Both the ocean and atmosphere are characterised by the basic vertical density stratification, and this feature can affect the dynamics on all scales ranging from the micro-scale to the planetary scale. The aim of this book is to provide a “state-of-the-art” account of stratified flows as they are relevant to the ocean and atmosphere with a primary focus on meso-scale phenomena; that is, on phenomena whose time and space scales are such that the density stratification is a dominant effect, so that frictional and diffusive effects on the one hand and the effects of the earth’s rotation on the other hand can be regarded as of less importance. This in turn leads to an emphasis on internal waves.

As the atmosphere and oceans feature density variations with depth, the flow of a density-stratified fluid over topography is central to various geophysical and meteorological applications and has been studied extensively. For reasons of convenience and mathematical tractability, the majority of theoretical treatments of stratified flow over a finite-amplitude obstacle assume idealized background flow conditions, namely constant free-stream velocity and either a homogeneous or two-layer buoyancy-frequency profile. In this work, a numerical model is developed that accounts for general variations in the buoyancy-frequency profile far upstream and the presence of unsteadiness in the free-stream velocity. The model employs a second-order projection method for solving the Euler equations for stratified flow over locally confined topography in a horizontally and vertically unbounded domain - the flow configuration most pertinent to atmospheric applications - combined with absorbing viscous layers at the upper and lateral boundaries of the computational domain. Using this model, a study is first made of the effect of variations in the buoyancy frequency on the generation of mountain gravity waves.

This book covers the theory of stratified flows, from basic concepts to recent developments in environmental fluid mechanics. State-of-the-art numerical techniques suited for stratified flows are given, along with results of recent research in the areas of environmental stratified flows. The book offers a unified view of stratified turbulent flows, from small-scale mixing to large-scale environmental phenomena, including detailed discussion on interaction between turbulence and internal gravity waves.

This text presents the key findings of the International Symposium held in Delft in 2003, which explored the process of shallow flows. Shallow flows are found in lowland rivers, lakes, estuaries, bays, coastal areas and in density-stratified atmospheres, and may be observed in puddles, as in oceans. They impact on the life and work of a w

The first papers of this conference addressed the long-standing issues of the nature of the upstream effects that occur in stratified flow over obstacles (P G Baines, CSIRO, Australia, A P Taylor, York University, Ontario, Canada; K W Ayotte, Boulder, Colorado, USA). Then followed a sessionon internal wave motions followed by a session on modelling the atmospheric boundary layer (J C King, British Antarctic Survey, Cambridge; A Kay, Loughborogh University of Technology). There was a session on numerical modelling (O Matais, Instite de Mecanique de Grenoble, France; A S Smedman,Uppsala University). The various aspects of dispersion were discussed and the final papers in the conference described laboratory experiments on flow and dispersion around buildings in light wind conditions.