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5 CONCLUSIONS
We began this chapter with an outline discussion on typical
bedforms found in uni-directional flows, focusing particularly
on sandwave morphology and traditional classification schemes.
As discussed, established methods of modelling the flow over
these bedforms have been by the extension of flat bed approaches
which are totally inappropriate for flows featuring pronounced
separation. More recently some basic concepts of shear layer
dynamics have been incorporated, but there is presently no
adequate engineering calculation method appropriate for these
flows. It seems unlikely that Eulerian integral models and twoequation
turbulence models alone will adequately reproduce the
important features responsible for sediment capture and
transport.
Related developments have also been discussed, concerning the
coherent eddy features responsible for sediment motion. Many
aspects of this are now reasonably well understood and
incorporated into modelling methodologies. However, there is
still a need for introducing more refined methods such as have
been developed for analogous aspects of bubbly flows; in
particular Lagrangian calculations based on discrete vortex
modelling, which can deliver a representation of the transient
large eddies and their propensity for attracting and retaining
particles.
This study focuses specifically on this propensity for particle
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