In this paper, the results of the characterization of Kamphorst’s rainfall simulator obtained by laboratory experiments carried out at the Department of Agricultural, Food, and Forest Sciences of the University of Palermo, are presented. At first, the rainfall uniformity distribution was positively verified considering several pressure heads (ranging from 1.9 cm to 11.9 cm) and water temperatures (from 24 °C to 27 °C), achieving a uniformity coefficient ranging from 96 to 99 %. Then, using a single nozzle, the simulator has been characterized in terms of kinetic power and momentum by applying both a photographic and a weighing technique. In particular, terminal drop velocity was measured by the displacement of a single raindrop measured between two consecutive frames, while the mean mass of single drops was evaluated by weighing a fixed number of drops. The analysis of the experimental data highlighted that the rainfall intensity, which increases with water temperature and pressure head, is the variable affecting the measurement of the single raindrop mass. Measurements also showed that an increase in rainfall intensity determines a decrease in the mean mass of the raindrops and an increase in the number of raindrops that fall in the unit time and area. This circumstance allowed to justify the increasing trend of the rainfall kinetic power and momentum with rainfall intensity. The measurements allowed to develop empirical relationships relating kinetic power and momentum with the simulated rainfall intensity and falling height of the raindrops. Finally, a theoretical expression suggested in the literature for estimating simulated rainfall intensity was positively tested.

中文翻译：

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表征用于土壤侵蚀调查的 Kamphorst 降雨模拟器


本文介绍了通过巴勒莫大学农业、食品和林业科学系进行的实验室实验获得的 Kamphorst 降雨模拟器的表征结果。首先，考虑多个压头（1.9厘米至11.9厘米）和水温（24℃至27℃）对降雨均匀性分布进行了积极验证，实现了96％至99％的均匀系数。然后，使用单个喷嘴，通过应用摄影和称重技术来表征模拟器的动能和动量。特别是，终端滴速度是通过在两个连续帧之间测量的单个雨滴的位移来测量的，而单个雨滴的平均质量是通过对固定数量的雨滴进行称重来评估的。对实验数据的分析表明，降雨强度随着水温和压头的增加而增加，是影响单个雨滴质量测量的变量。测量还表明，降雨强度的增加决定了雨滴平均质量的减少以及单位时间和面积内落下的雨滴数量的增加。这种情况证明了降雨动能和动量随降雨强度的增加趋势是合理的。通过测量，可以建立动能和动量与模拟降雨强度和雨滴下落高度之间的经验关系。最后，对文献中提出的用于估计模拟降雨强度的理论表达式进行了积极测试。