Premium
Turbulent flow structures and aeolian sediment transport over a barchan sand dune
Author(s) -
Wiggs G. F. S.,
Weaver C. M.
Publication year - 2012
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2012gl050847
Subject(s) - geology , crest , turbulence , aeolian processes , sediment transport , geomorphology , airflow , bedform , shear velocity , wind speed , geotechnical engineering , meteorology , sediment , oceanography , physics , optics , thermodynamics
The turbulent structure of airflow over a barchan sand dune is determined using quadrant analysis of wind velocity data derived from sonic anemometers. Results indicate an increased frequency of ejection and sweep events in the toe region of the dune, characteristic of the turbulent bursting process. In contrast, at the crest there was a significant increase in the occurrence of outward interactions. Combined with high frequency saltation data our analyses show that turbulent structures characterised by a positive streamwise fluctuating velocity ( +u′ ; sweeps at the toe and outward interactions at the crest) have a dominant influence on sand transport on the dune, together accounting for up to 83% and 95% of transporting events at the toe and crest respectively.