Wind tunnel tests of the dynamic processes that control wind erosion of a sand bed

Abstract

Aeolian sand transport is a complicated process that is affected by many factors (e.g. wind velocity, sand particle size, surface microtopography). Under different experimental conditions, erosion processes will therefore produce different results. In this study, we conducted a series of wind tunnel experiments across a range of wind velocities capable of entraining sand particles (8.0, 10.0, 12.0, and 14.0 m s‐1) to study the dynamic changes of the shear velocity, aerodynamic roughness length, and sand transport. We found that the shear velocity and aerodynamic roughness length are not constant; rather, they change dynamically over time, and the rules that describe their changes depend on the free‐stream air velocity. For wind tunnel experiments without feeding sand into the airflow, the sand bed elevation decreases with increasing erosion time, and this change significantly affected the values of shear velocity and aerodynamic roughness length. A Gaussian distribution function described the relationships between the sand transport rate (qT) and the duration of wind erosion (T). It is therefore necessary for modelers to consider both deflation of the bed and the time scale used when calculating sand transport or erosion rates. © 2018 John Wiley & Sons, Ltd.

Studying the spatial and temporal changes in aeolian sand transport in a wind tunnel using 3D terrestrial laser scanning

“…Using this design, a logarithmic boundary layer that was 0.7 m thick was produced ( Figure S1) in the wind tunnel. Wang et al (2018) provided a detailed description of this wind tunnel. In the present experiment, wind velocities at the height of 0.7 m were measured 5 m downwind of the sand bed margin with pitot tubes.…”

“…Specifically, many researchers have proven that both the height and wavelength of the ripples increased with increasing erosion duration and wind velocity (e.g., Andreotti et al, 2006;McKenna Neuman & Bédard, 2017;Sharp, 1963). This suggests that the shear velocity and aerodynamic roughness length calculated from the wind profile should be affected by the changes of RMSH (Field & Pelletier, 2018;Wang et al, 2018).…”

Wind Tunnel Test on Windblown Sand Two-Phase Flow Characteristics in Arid Desert Regions

“…Removable sand chamber Inclination 30°W edge-shaped leading edge The wind speed profile in the windblown sand flow field is obtained by the wind profiler (Figure 3) placed behind the sand trays, which is specially used for windblown sand tunnel tests [33,[43][44][45]. The wind profiler with a deviation of 0.15% of the measured value has 9 probes in the range of 1 m (mounted at 5 mm, 10 mm, 15 mm, 50 mm, 100 mm, 250 mm, 500 mm, 750 mm and 1000 mm) [33].…”

“…It is difficult to consider the geometric scaling of sand particles because the particle size is less than 1 mm. Therefore, according to the existing windblown sand tests [33,35,40,44,45], we ignored the influence of the geometric scaling of sand particles on the results. The impurity-free wind flow field in desert regions is simulated by using artificial roughness with baffles, roughness elements and spires in the wind tunnel (Figure 1).…”

Investigating the impact factors of dust emission efficiency over gobi with portable wind tunnel field experiments

“…Indeed, some research reported that the correlation between dust flux and u à changes at the different stage of experimental processes (Houser & Nickling, 2001;Wang et al, 2018). The relationship between η and u à and the underlying mechanisms are still unclear by experimental studies (Kok et al, 2012).…”