Tholen K, Pähtz T, Kamath S, Parteli EJR, Kroy K. Anomalous Scaling of Aeolian Sand Transport Reveals Coupling to Bed Rheology.
PHYSICAL REVIEW LETTERS 2023;
130:058204. [PMID:
36800459 DOI:
10.1103/physrevlett.130.058204]
[Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/05/2022] [Accepted: 01/05/2023] [Indexed: 06/18/2023]
Abstract
Predicting transport rates of windblown sand is a central problem in aeolian research, with implications for climate, environmental, and planetary sciences. Though studied since the 1930s, the underlying many-body dynamics is still incompletely understood, as underscored by the recent empirical discovery of an unexpected third-root scaling in the particle-fluid density ratio. Here, by means of grain-scale simulations and analytical modeling, we elucidate how a complex coupling between grain-bed collisions and granular creep within the sand bed yields a dilatancy-enhanced bed erodibility. Our minimal saltation model robustly predicts both the observed scaling and a new undersaturated steady transport state that we confirm by simulations for rarefied atmospheres.
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