Abstract
Over the last few decades, there has been considerable interest in gravity waves in stratified (variable density) flow over topography. This has been motivated in the main by studies of windflow in the atmosphere, where gravity wave propagation and wave overturning can influence considerably the results of both large scale meteorological models and smaller models based on specific sites. Most experimental and theoretical work, however, has involved studies of stably stratified fluids flowing over isolated topography of carefully calculated functional form. This thesis is in two main parts; the first is a literature review, containing an introduction to some of the parameters appropriate to the classification of stratified flows and a review of some of the more prominent studies that have been conducted using various approximations to the governing equations of motion. These include Linear theory, Long's Model, anelastic approximations and incompressible models (both weakly and fully nonlinear). This section also contains brief introductions to turbulence models and experimental studies. The second part of this thesis reports on research conducted into the implementation of a viscous upper layer boundary condition (designed to absorb any vertically propagating waves) in the standard Surrey stratified flow numerical codes. The results of testing the modification for two dimensional high Reynolds number flows over a fence and short and long cosine hills are presented, with conclusions and a number of further suggestions made in the final chapter.