Permanent link to this recordhttp://hdl.handle.net/10754/661687
MetadataShow full item record
AbstractSandstorms are frequently accompanied by intense electric fields and lightning. In a very narrow region close to the ground, sand particles undergo a charge exchange during which larger-sized sand grains become positively charged and smaller-sized sand grains become negatively charged, and then all particles become suspended by the turbulent fluid motion. Although the association of intense electric fields with sandstorms has long been observed, the mechanism that causes these intense electric fields has not yet been described. Here, we hypothesize that differently sized sand particles are differentially transported by turbulence in the flow, resulting in a large-scale charge separation and a consequential large-scale electric field. To confirm our hypothesis, we combined a large-eddy simulation framework comprising a turbulent atmospheric boundary layer and movement of sand particles with an electrostatic Gauss law to investigate the physics of the electric fields in sandstorms. We varied the strength of the sandstorm from weak to strong as parametrized by the number density of the entrained sand particles. Our simulations reproduced observational measurements of both mean and root mean squared fluctuation values of the electric field. Our results allowed us to propose a law in which the electric field scales to two-thirds of the power of the concentration of the sand particles in weak to medium strength sandstorms.
CitationRahman, M. M., Cheng, W., & Samtaney, R. (2021). Generation and sustenance of electric fields in sandstorms. Physical Review Research, 3(1). doi:10.1103/physrevresearch.3.l012008
SponsorsThis paper was supported by KAUST under Awards No. URF/1/1704-01-01 and No. BAS/1/1/1349-01-1. Cray XC40—Shaheen-II was used for simulations.
PublisherAmerican Physical Society (APS)
JournalPhysical Review Research
Except where otherwise noted, this item's license is described as Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI.