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AGU: Geophysical Research Letters

 

Index Terms

  • Planetary Sciences: Solid Surface Planets: Atmospheres
  • Planetary Sciences: Solar System Objects: Dust
  • Planetary Sciences: Solar System Objects: Mars

Abstract

GEOPHYSICAL RESEARCH LETTERS, VOL. 33, L19S09, 5 PP., 2006
doi:10.1029/2006GL026810

Dust flux within dust devils: Preliminary laboratory simulations

Lynn D. V. Neakrase

Department of Geological Sciences, Arizona State University, Tempe, Arizona, USA

Ronald Greeley

Department of Geological Sciences, Arizona State University, Tempe, Arizona, USA

James D. Iversen

Department of Aerospace Engineering, Iowa State University, Ames, Iowa, USA

M. R. Balme

Department of Earth Sciences, Open University, Milton Keynes, UK

Eric E. Eddlemon

Planetary Aeolian Facility, NASA Ames Research Center, Moffett Field, California, USA

Laboratory simulations using the Arizona State University Vortex Generator (ASUVG) were run to simulate dust flux in dust devils. These tests used particles 2 μm in diameter and 2600 kg m−3 in density, and the results were compared with data from natural dust devils on Earth and Mars. Typically, the cores of dust devils (regardless of planetary environment) have a pressure drop of ∼0.2–1.5 percent of ambient atmospheric pressure. Core pressure drops in our experiments ranged from ∼0.01 to 5.00 percent of ambient pressure (10 mbar Mars cases and 1000 mbar for Earth cases). Flux experiments were run at vortex tangential wind velocities of 1 to 42 m s−1; typically ∼35–50 percent above threshold values for the particles used. Dust flux was determined by time averaged measurements of mass loss for a given vortex size. Dust fluxes of ∼10−3 kg m−2 s−1 were obtained, similar to estimates for flux for dust devils on Earth and Mars, regardless of core size. Vortex strength appears to be closely related to the strength of the pressure drop in the core (ΔP) and is less determined by size of the vortex. This is critical in scaling the laboratory results to natural dust devils.

Received 4 May 2006; accepted 14 August 2006; published 23 September 2006.

Citation: Neakrase, L. D. V., R. Greeley, J. D. Iversen, M. R. Balme, and E. E. Eddlemon (2006), Dust flux within dust devils: Preliminary laboratory simulations, Geophys. Res. Lett., 33, L19S09, doi:10.1029/2006GL026810.

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