Laboratory Simulation of Aeolian Sand
Transport and Physical Modeling of Flow Around Dunes
Bruce R. White
Department
of Mechanical and Aeronautical Engineering
University
of California, Davis
Overview
This
paper discusses the possibilities of laboratory simulation of large-scale flow
around dunes, both with and without saltation, and the study of the physics of
the small-scale particle motion occurring on a sand surface composed of
like-moveable particles. Physics of the atmospheric boundary layer are
presented in the context of laboratory applications. The governing equations of
fluid and/or particle motion are discussed and analyzed for applications in
laboratory testing. The most important similitude parameters, as applied to wind-tunnel
requirements for conservation of mass, momentum, energy, and the boundary
conditions are presented and discussed. Key findings and results are that: i)
in general, flow around a dune or multiple dunes with saltation present cannot
be accurately simulated in wind tunnels; ii) flow field around all or part of a
full-scale dune can be simulated marginally in a wind tunnel, provided “large”
model scales and “reasonably high” wind-tunnel speeds are used (the conditions
of “large” model scales and “reasonably high” speeds are specified within the
text); and, iii) it is possible to accurately replicate the process of
saltation in wind tunnels provided appropriate similitude and independence
criteria of Reynolds and Froude numbers are observed. Limited laboratory and
wind-tunnel studies are cited.
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