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PhysRevResearch.3.L012008.pdf
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Type
ArticleKAUST Grant Number
URF/1/1704-01-01BAS/1/1/1349-01-1
Date
2021-01-20Submitted Date
2020-02-03Permanent link to this record
http://hdl.handle.net/10754/661687
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Sandstorms 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.Citation
Rahman, 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.l012008Sponsors
This 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.Publisher
American Physical Society (APS)Journal
Physical Review ResearcharXiv
2001.11503Additional Links
https://link.aps.org/doi/10.1103/PhysRevResearch.3.L012008ae974a485f413a2113503eed53cd6c53
10.1103/physrevresearch.3.l012008
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