Effects of plants with different shapes and coverage on the blown-sand flux and roughness length examined by wind tunnel experiments

Plants can reduce the effects of wind erosion on erodible surfaces by absorbing momentum near sandy surfaces. We used models having the same cross-sectional shape as three common plants in the arid regions of Mongolia and carried out tests in a wind tunnel equipped with a turbulence generator and a piezoelectric blown-sand meter. We studied the effects of plant shape and coverage on the sand accumulation amount, roughness length, and blown-sand flux. With a cone array or an inverted truncated cone array, roughness length increased as the modeled plant coverage increased up to 21.1%, similar to the accumulation amount trend. With a cylinder array, however, roughness length reached a maximum at 6.6% coverage and then gradually decreased. The accumulation amount also trended downward at coverages greater than 15.4%, a change we attributed to changes in the wake distribution. In addition, the wind-blown-sand flux results showed that a cylinder array had a strong inhibitory effect on the blown-sand flux at heights above 10 cm, whereas the inhibitory effect of a cone array was small. Moreover, with an inverted truncated cone array, the suppression effect on the flux below 10 cm was similar to that with the cone array, and the suppression effect on the flux above 10 cm was more pronounced than that with a cylinder array. Our results can be applied to evaluate how shape affects the suitability of a plant for reducing wind erosion in southern Mongolia and potentially in other arid and semi-arid regions.

Automated summary

The study found that plant shape and coverage have an impact on sand accumulation amount, roughness length, and blown-sand flux. Cone and inverted truncated cone-shaped plants exhibit strong inhibitory effects on blown-sand flux, while cylindrical plants have a strong inhibitory effect on blown-sand flux at greater heights.