Effects of wind on rainfall simulation : spatial distribution of water application, kinetic energy, and overland flow under single full-cone nozzle sprays

摘要: Portable rainfall simulators used in small plots give sufficient flexibility to study a wide variety of processes (e.g. infiltration, interrill erosion, water quality) on different soils and slopes for range land uses. They also allow number repetitions short period time. In conducting these studies, it is important measure the characteristics simulated applied test surface. It unquestionable that wind affects field experiments make use simulators. Water-drop trajectories velocities are altered, affecting application, kinetic energy distributions, hydraulics underlying overland flow, namely depths velocities. A three-dimensional numerical model was developed from movement physical conditions individual drops, order estimate distances times which necessary them reach ground after their release nozzle simulator. The original momentum drop affected by drag forces, gravity. logarithmic profile above soil surface assumed all situations. Water application distributions were estimated coupling hydrodynamic movement, stochastic generator representing single full-cone spray nozzle, an appropriate interception algorithm at hydraulic flow strongly related properties spatial variability rainfall. distribution intensity, mean size, incidence angles have been combined with analysis shear stress water-air boundary, influence mechanics under spraying systems. This done driving force plane. mathematical presented this paper should facilitate selection spray-nozzles (spray angles, ejection velocities, drop-size distribution) size configuration area expected situations (rainfall characteristics, conditions, slope terrain, plot size). provides simple way visualizing patterns sloping surfaces conditions. Page 2 RAINFALL SIMULATION