Physics
Scientific paper
Dec 2004
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2004agufm.p31b0989c&link_type=abstract
American Geophysical Union, Fall Meeting 2004, abstract #P31B-0989
Physics
5415 Erosion And Weathering, 5470 Surface Materials And Properties, 5494 Instruments And Techniques, 1625 Geomorphology And Weathering (1824, 1886)
Scientific paper
Sand is deposited on the lee slope of dunes by grainfall, avalanching (grainflow), and wind ripple migration. These processes play major roles in the formation of aeolian cross strata. Grainfall is produced by saltating grains that are blown over the dune crest and fall on the lee slope. Avalanching occurs when sand on the lee slope fails and the resulting grainflow will deposit tongues of sand downslope. Lee slope deposits are often preserved in the rock record and an understanding of the conditions that produce them as well as avalanche frequency and magnitude could provide important information about dune morphology, sediment flux and availability, air flow, and the environment of deposition. Despite their importance there have been very few studies of grainfall and avalanching because the lee slope of dunes is a very fragile and easily disturbed environment. Designing research strategies to study these processes presents significant technical challenges. To overcome these obstacles construction and testing of a dune simulation wind tunnel was recently completed as a joint project between the Wind Erosion Laboratory, Department of Geography, University of Guelph and the Desert Research Institute. This wind tunnel contains a small, but true-scale sand dune that is 8.5 m long, 1.2 m high, and 1 m wide and is capable of producing wind speeds of 16 m/s at 30cm above the dune crest. The wind tunnel provides an opportunity to study lee slope processes in a well-constrained environment by controlling wind speeds and direction, dune geometry and composition, and allows for extensive instrumentation and close observation of depositional processes. Preliminary experiments in the dune simulation wind tunnel indicate that avalanche frequency is predictable: increased wind speeds resulted in more frequent avalanches. Avalanches commonly originate in the mid-lee slope region at or near the point of reattachment of the return cell caused by flow separation at the crest. Downslope saltation and/or reptation on the lee slope surface appear to slow at the point of reattachment and appears to be an important factor in the location of avalanche origination. Preliminary measurements of the distribution of sediment deposited by grainfall at three different wind speeds suggest a possible depositional bulge in the mid-lee slope region. Research supported by NSF EAR-0207833
Cupp K.
Lancaster Nick
Nickling William G.
No associations
LandOfFree
A Dune Simulation Wind Tunnel for Studies of Lee Face Processes does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with A Dune Simulation Wind Tunnel for Studies of Lee Face Processes, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and A Dune Simulation Wind Tunnel for Studies of Lee Face Processes will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-1453268