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United States Department of Agriculture

Agricultural Research Service

Title: The Effect of Wind on Physical Raindrop Impact and Rainsplash Detachment

Authors
item Erpul, G - UNIV. OF ANKARA
item Norton, Lloyd
item Gabriels, D - GHENT UNIVERSITY

Submitted to: Soil Erosion Patterns Evolution Spatio Temporal Dynamics and Connectivity
Publication Type: Proceedings
Publication Acceptance Date: October 1, 2002
Publication Date: October 10, 2002
Citation: ERPUL, G., NORTON, L.D., GABRIELS, D. THE EFFECT OF WIND ON PHYSICAL RAINDROP IMPACT AND RAINSPLASH DETACHMENT. SOIL EROSION PATTERNS EVOLUTION SPATIO TEMPORAL DYNAMICS AND CONNECTIVITY. 2002. Abstract. p. 8.

Technical Abstract: In wind-driven rains, variations in raindrop trajectory and frequency are expected due to the changes in the angle of raindrop incidence. This paper presents experimental data obtained on the effects of horizontal wind velocity on physical raindrop impact and rainsplash detachment. In a wind tunnel facility equipped with a rainfall simulator, windless rains and the rains driven by horizontal wind velocities of 6, 10, and 14 ms-1 were applied to three agricultural soils packed into 20 by 55 cm soil pan at both windward and leeward slopes of 7, 15, and 20%. Rain intensity was directly measured with inclined rain gauges with respect to the prevailing wind direction. These measurements showed that the actual amount of rainfall intercepted on the soil surface varied 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, considering forces that act on a raindrop falling through a wind field. 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 results showed that the wind not only increased the raindrop resultant 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.

Last Modified: 7/23/2014
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