عنوان مقاله [English]
نویسندگان [English]چکیده [English]
Rainfall simulation is frequently employed in soil erosion and related processes studies. A rainfall simulator was constructed in Soil Conservation and Watershed Management Research Institute (SCWMRI), which is superior to other existing simulators in country. This simulator consists of some parts such as; water supply, rainfall boom, tilting flume, runoff collection and storage system, control keyboard and laboratory. Rainfall boom has 6 nozzles which introduce a distribution of drop sizes from height of 7.75 m. Tilting flume consists of flow generation section, drainage part, slope control facility adjusting to 60%, and runoff collection system. Rain Intensity can be controlled by water pressure, number of active nozzles, their distance and pattern, so different intensities ranges 35 to 125 mm h-1 are simulated with coefficient of uniformity more than 90%. Depending on rain intensity, mean drops diameter varies from 1.64 to 2.15 mm and terminal velocity ranges 5.70 to 6.78 m s-1. Besides, the kinetic energy of falling drops varies from 16.24 to 22.97 J m-2 s-1. This simulator can generate rainfall and or runoff separately or simultaneously. So, it is possible to study rain-driven and or flow- driven processes under laboratory conditions.