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Register a new userSpatiotemporal Structure of Aeolian Particle Transport on Flat Surface
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We conduct numerical simulations based on a model of blowing snow to reveal the long-term properties and equilibrium state of aeolian particle transport from $10^{-5} hspace{0.5 ex} mathrm{m}$ to $10 hspace{0.5 ex} mathrm{m}$ above the flat surface. The numerical results are as follows. (i) Time-series data of particle transport are divided into development, relaxation, and equilibrium phases, which are formed by rapid wind response below $10 hspace{0.5 ex} mathrm{cm}$ and gradual wind response above $10 hspace{0.5 ex} mathrm{cm}$. (ii) The particle transport rate at equilibrium is expressed as a power function of friction velocity, and the index of 2.35 implies that most particles are transported by saltation. (iii) The friction velocity below $100 hspace{0.5 ex} mumathrm{m}$ remains roughly constant and lower than the fluid threshold at equilibrium. (iv) The mean particle speed above $300 hspace{0.5 ex} mumathrm{m}$ is less than the wind speed, whereas that below $300 hspace{0.5 ex} mumathrm{m}$ exceeds the wind speed because of descending particles. (v) The particle diameter increases with height in the saltation layer, and the relationship is expressed as a power function. Through comparisons with the previously reported random-flight model, we find a crucial problem that empirical splash functions cannot reproduce particle dynamics at a relatively high wind speed.
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