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Record Details

Record 3 of 59373
Martian Dust Devils: Laboratory Simulations of Particle Threshold
External Online Source: doi:10.1029/2002JE001987
Author and Affiliation:
Greeley, Ronald(Arizona State Univ., Dept. of Geological Sciences, Tempe, AZ, United States)
Balme, Matthew R.(Arizona State Univ., Dept. of Geological Sciences, Tempe, AZ, United States)
Iverson, James D.(Iowa State Univ. of Science and Technology, Aerospace Engineering and Engineering Mechanics Dept., Ames, IA, United States)
Metzger, Stephen(Nevada Univ., Dept. of Geological Sciences, Reno, NV, United States)
Mickelson, Robert(Mickelson (Robert), Phoenix, AZ, United States)
Phoreman, Jim(NASA Ames Research Center, Moffett Field, CA, United States)
White, Bruce(California Univ., Dept. of Mechanical and Aerospace Engineering, Davis, CA, United States)
Abstract: An apparatus has been fabricated to simulate terrestrial and Martian dust devils. Comparisons of surface pressure profiles through the vortex core generated in the apparatus with both those in natural dust devils on Earth and those inferred for Mars are similar and are consistent with theoretical Rankine vortex models. Experiments to determine particle threshold under Earth ambient atmospheric pressures show that sand (particles > 60 micron in diameter) threshold is analogous to normal boundary-layer shear, in which the rotating winds of the vortex generate surface shear and hence lift. Lower-pressure experiments down to approx. 65 mbar follow this trend for sand-sized particles. However, smaller particles (i.e., dust) and all particles at very low pressures (w 10-60 mbar) appear to be subjected to an additional lift function interpreted to result from the strong decrease in atmospheric pressure centered beneath the vortex core. Initial results suggest that the wind speeds required for the entrainment of grains approx. 2 microns in diameter (i.e., Martian dust sizes) are about half those required for entrainment by boundary layer winds on both Earth and Mars.
Publication Date: Jan 01, 2003
Document ID:
20030073471
(Acquired Oct 08, 2003)
Subject Category: LUNAR AND PLANETARY SCIENCE AND EXPLORATION
Report/Patent Number: ASU-PVA-6554/TE
Document Type: Journal Article
Publication Information: Journal of Geophysical Research; p. 7-1; (ISSN 0148-0227); Volume 108; No. E5
Publisher Information: American Geophysical Union, United States
Contract/Grant/Task Num: NCC2-1109
Financial Sponsor: NASA Ames Research Center; Moffett Field, CA, United States
Organization Source: NASA Ames Research Center; Moffett Field, CA, United States
Description: 1p; In English
Distribution Limits: Unclassified; Publicly available; Unlimited
Rights: Copyright
NASA Terms: SPACE ENVIRONMENT SIMULATION; DUST STORMS; MARS ENVIRONMENT; COSMIC DUST; MARS SURFACE; WIND EFFECTS; MARS ATMOSPHERE; PLANETARY METEOROLOGY; WIND (METEOROLOGY); MARS (PLANET); SANDS; ATMOSPHERIC BOUNDARY LAYER; VORTICES; SHEAR FLOW; LOW PRESSURE; WIND VELOCITY
Availability Source: Other Sources
Availability Notes: Abstract Only
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