Large-eddy simulation (LES) is a method for resolving the
time-dependent structure of high Reynolds number, turbulent flows. With
LES it is possible to model and track the behaviour of coherent
turbulent structures and study their effect on the flow field. Hence,
LES is potentially an important research tool in the fluvial sciences
where flow mixing, sediment entrainment and sediment transport are all
affected by the presence of coherent vortices and their interactions
with channel boundaries and other flow structures. This paper
introduces the LES methodology, discusses a variety of ways for
representing small-scale processes within LES (the subgrid-scale
modelling problem), and provides some examples of early work into the
use of LES in a fluvial context. A number of advances in computational
power and numerical methods are required before LES can be effectively
applied at the river reach scale. This paper considers some recent
developments and their potential for providing validated large-eddy
simulations of river flow at the channel scale. (c) 2005 Elsevier B.V.
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