Article,
Study of Aerodynamic Grain Entrainment in Aeolian Transport
GEOPHYSICAL RESEARCH LETTERS, (2020)
DOI: 10.1029/2019GL086574
Abstract
Aeolian transport controls landform formations on Earth and other
planets and crucially affects the atmospheric system. With elaborate
wind tunnel measurements, we find that the aerodynamic entrainment rate
follows a yet unreported exponential increase in the intermittent regime
and only complies with the expected linear law for the condition of
continuous entrainment. Subsequently, we propose a model accounting for
the effects of turbulence on aerodynamic entrainment based on the
distribution of local shear stress to describe the experimental results.
We also provide evidence that aerodynamic entrainment can be an
efficient way to directly induce a horizontal grain transport comparable
to the steady and saturated saltation in unsaturated conditions and
should not be ignored. Our findings substantially modify the present
interpretation of surface erosion and bear thus important consequences
on future soil protection techniques.
