Aeolian Sand Transport in Out-of-Equilibrium Regimes

Autor: Selmani, H., Valance, Alexandre, Ould El Moctar, A., Dupont, Patrick, Zegadi, R.
Přispěvatelé: Institut de Physique de Rennes (IPR), Université de Rennes (UR)-Centre National de la Recherche Scientifique (CNRS), Université Ferhat-Abbas Sétif 1 [Sétif] (UFAS1), Laboratoire de Thermique et d’Energie de Nantes (LTeN), Ecole Polytechnique de l'Université de Nantes (EPUN), Université de Nantes (UN)-Université de Nantes (UN)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Génie Civil et Génie Mécanique (LGCGM), Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA), PNE 2015-2016, Algerian Ministry of Higher Education and Scientific Research, Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Centre National de la Recherche Scientifique (CNRS), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)
Jazyk: angličtina
Rok vydání: 2018
Předmět:
Zdroj: Geophysical Research Letters
Geophysical Research Letters, 2018, 45 (4), pp.1838-1844. ⟨10.1002/2017GL076937⟩
Geophysical Research Letters, American Geophysical Union, 2018, 45 (4), pp.1838-1844. ⟨10.1002/2017GL076937⟩
ISSN: 0094-8276
1944-8007
DOI: 10.1002/2017GL076937⟩
Popis: International audience; We investigate the relaxation process toward the equilibrium regime of saltation transport in the context of nonuniform conditions. Relaxation phenomena can be described in terms of a characteristic length scale that measures the distance for the particle flux to adapt to a spatial change in flow or boundary conditions. We conducted wind tunnel experiments to document the influence of the upwind mass flux on the relaxation process. For zero upwind mass flux conditions, the relaxation process is monotone and the relaxation length is independent of the wind strength. In contrast, for nonzero upwind flux conditions (obtained by releasing particles in the flow from a finite height), the relaxation process is nonmonotone and is well captured by damped harmonic oscillations. Importantly, the relaxation length increases with increasing air flow velocity but is almost insensitive to the magnitude of the upwind flux. Our experimental outcomes clearly indicate that the relaxation of far from equilibrium transport regimes strongly deviates from a simple exponential behavior.
Databáze: OpenAIRE
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