HR: 0800h
AN: H41F-0839    [Abstracts]
TI: Experiments on Bedforms Created by Density Currents
AU: * Fedele, J J
EM: jjfedele@stcloudstate.edu
AF: St Cloud State University, Wick Science Building 51, St Cloud, MN 56301, United States
AU: Hoyal, D C
EM: david.c.hoya@exxonmobil.com
AF: ExxonMobil Upstream Research, P.O. Box 2189, Houston, TX 77252-2189, United States
AU: Sheets, B A
EM: benjamin.a.sheets@exxonmobil.com
AF: ExxonMobil Upstream Research, P.O. Box 2189, Houston, TX 77252-2189, United States
AB: Small-scale bedforms such as dunes and ripples formed by density underflows such as density or turbidity currents are poorly understood. The general practice is to extrapolate bedform diagrams that were obtained from subaerial rivers and laboratory open channels to the case of deep water undercurrents, assuming that different bedforms created by density or turbidity currents form under similar flow regimes as in rivers (i.e. subcritical or supercritical). However, the validity of this assumption has never been tested. We present experimental evidence that dunes (commonly associated with low Froude number flows) could be formed in critical or supercritical saline density currents. Based on our findings and measurements, we also present a scaling analysis showing that these particular bedforms could indeed be associated with what sedimentologists and fluvial geomorphologists call dunes. Our findings have important implications from a mechanistic and geologic perspective, as they imply that a wider, and not yet fully investigated and understood, spectrum of bedforms due to gravity underflows might exist.
DE: 1824 Geomorphology: general (1625)
DE: 1862 Sediment transport (4558)
SC: Hydrology [H]
MN: 2007 Fall Meeting