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Dust devil dynamics
Author(s) -
Horton W.,
Miura H.,
Onishchenko O.,
Couedel L.,
Arnas C.,
Escarguel A.,
Benkadda S.,
Fedun V.
Publication year - 2016
Publication title -
journal of geophysical research: atmospheres
Language(s) - English
Resource type - Journals
eISSN - 2169-8996
pISSN - 2169-897X
DOI - 10.1002/2016jd024832
Subject(s) - vortex , mechanics , toroid , physics , vorticity , instability , nonlinear system , convection , temperature gradient , flow (mathematics) , classical mechanics , meteorology , plasma , quantum mechanics
A self‐consistent hydrodynamic model for the solar heating‐driven onset of a dust devil vortex is derived and analyzed. The toroidal flows and vertical velocity fields are driven by an instability that arises from the inversion of the mass density stratification produced by solar heating of the sandy surface soil. The nonlinear dynamics in the primary temperature gradient‐driven vertical airflows drives a secondary toroidal vortex flow through a parametric interaction in the nonlinear structures. While an external tangential shear flow may initiate energy transfer to the toroidal vortex flow, the nonlinear interactions dominate the transfer of vertical‐radial flows into a fast toroidal flow. This secondary flow has a vertical vorticity, while the primary thermal gradient‐driven flow produces the toroidal vorticity. Simulations for the complex nonlinear structure are carried out with the passive convection of sand as test particles. Triboelectric charging modeling of the dust is used to estimate the charging of the sand particles. Parameters for a Dust Devil laboratory experiment are proposed considering various working gases and dust particle parameters. The nonlinear dynamics of the toroidal flow driven by the temperature gradient is of generic interest for both neutral gases and plasmas.