Saltation of non-spherical sand particles

PLoS One. 2014 Aug 29;9(8):e105208. doi: 10.1371/journal.pone.0105208. eCollection 2014.

Abstract

Saltation is an important geological process and the primary source of atmospheric mineral dust aerosols. Unfortunately, no studies to date have been able to precisely reproduce the saltation process because of the simplified theoretical models used. For example, sand particles in most of the existing wind sand movement models are considered to be spherical, the effects of the sand shape on the structure of the wind sand flow are rarely studied, and the effect of mid-air collision is usually neglected. In fact, sand grains are rarely round in natural environments. In this paper, we first analyzed the drag coefficients, drag forces, and starting friction wind speeds of sand grains with different shapes in the saltation process, then established a sand saltation model that considers the coupling effect between wind and the sand grains, the effect of the mid-air collision of sand grains, and the effect of the sand grain shape. Based on this model, the saltation process and sand transport rate of non-spherical sand particles were simulated. The results show that the sand shape has a significant impact on the saltation process; for the same wind speed, the sand transport rates varied for different shapes of sand grains by as much as several-fold. Therefore, sand shape is one of the important factors affecting wind-sand movement.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aerosols / analysis*
  • Air Pollutants / analysis*
  • Dust / analysis*
  • Environmental Monitoring
  • Friction
  • Minerals / analysis*
  • Models, Chemical
  • Particle Size
  • Wind

Substances

  • Aerosols
  • Air Pollutants
  • Dust
  • Minerals

Grants and funding

This work is supported by the National Key Basic Research and Development Program (“973” Program) (2009CB421304), the Innovative Research Groups of the National Natural Science Foundation of China (11121202), the National Natural Science Foundation of China (11172118, 41371034, 91325203), and the National Key Technologies R & D Program of China (2013BAC07B01). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.