Akademik Veri Yönetim Sistemi
TRANSACTIONS OF THE ASAE, cilt.46, sa.1, ss.51-62, 2003 (SCI-Expanded)
In wind-driven rains, variations in raindrop trajectory and frequency are expected due to the changes in the angle of raindrop incidence. This article presents experimental data on-the effects of horizontal wind velocity on rainsplash detachment. In a wind tunnel facility equipped with a rainfall simulator, windless rains and rains driven by horizontal wind velocities of 6, 10, and 14 m s(-1) were applied to three agricultural soils packed into 20 x 55 cm soil pans with both windward and leeward slopes of 7%, 15%, and 20%. Rain intensity was directly-measured with inclined raingauges oriented with respect to the prevailing wind direction: These measurements showed that the actual amount of rainfall intercepted on the soil surface varied widely depending on the angle of rain incidence, which was a function of the rain inclination and slope gradient and aspect. A two-dimensional numerical model was used to estimate wind-driven raindrop trajectories. Rain energy was also measured by a kinetic energy sensor. Theory and measurement showed that an exponential relationship existed between the energy of simulated rainfall and the applied horizontal wind velocity. The experiments led to the conclusion that the wind not only increased the resultant raindrop impact velocity but also altered the angle of raindrop incidence, resulting in variable raindrop impact frequency and impact angle. Accordingly, differential rainsplash detachment occurred depending on the changes in raindrop trajectory and frequency with wind velocity and direction. There were significant differences in the detachment rates between the aspects, and the rates were as much as 44 times greater in the windward slopes than in the leeward slope.