Analytical mesoscale modeling of aeolian sand transport

TL;DR

This paper develops and verifies an analytical mesoscale model of aeolian sand transport based on grain-scale kinetics, successfully matching field and wind tunnel data and clarifying the role of turbulence in dune formation.

Contribution

It introduces a novel coarse-grained analytical model of aeolian sand transport that incorporates grain-scale physics and splash statistics, validated by numerical simulations.

Findings

Model accurately predicts height-resolved sand flux.

Reconciles previous conflicting models of dune size.

Highlights importance of turbulent fluctuations in sand transport.

Abstract

The mesoscale structure of aeolian sand transport determines a variety of natural phenomena studied in planetary and Earth science. We analyze it theoretically beyond the mean-field level, based on the grain-scale transport kinetics and splash statistics. A coarse-grained analytical model is proposed and verified by numerical simulations resolving individual grain trajectories. The predicted height-resolved sand flux and other important characteristics of the aeolian transport layer agree remarkably well with a comprehensive compilation of field and wind tunnel data, suggesting that the model robustly captures the essential mesoscale physics. By comparing the saturation length with field data for the minimum sand-dune size, we can reconcile conflicting previous models for this most enigmatic emergent aeolian scale and elucidate the importance of intermittent turbulent wind fluctuations for field measurements.