COMPUTER-CONTROLLED VARIABLE INTENSITY RAIN SIMULATOR

Natural rainstorms have dynamic intensities; thus, a large portion of total precipitation may be received during a short time, Natural rains torms also have both variable drop sizes and kinetic energy, Accurate studies of sediment transport and infiltration require realistic dupli cation of natural rain kinetic energy and intensities, Rain simulator designs must be capable of producing dynamic multiple intensities and corresponding multiple drop sizes to simulate variable kinetic energie s, Many simulators are capable of producing rain with multiple and, in some cases, dynamic intensities, but a simulator that can vary both t he intensity and kinetic energy is needed, Our objective was to design and build a rain simulator for field use that realistically duplicate d natural rain storms. A computer-controlled solenoid-valve multiple n ozzle type rain simulator was developed, The computer not only control s solenoid valve activation of the rain simulator during operation but also measures runoff and records rain application and runoff data to a log file for processing. The simulator has control software that con trols and monitors all processes, The rain simulator is capable of uni formly applying water (coefficient of uniformity = 84-94%) with a dyna mically changing intensity of up to 200 mm h(-1) and kinetic energies ranging from 15.0 to 23.5 J m(-2) mm(-1). Uniformity of application wa s achieved by oscillating the nozzles in two directions, Field operati on of the simulator is enhanced by its portability, The measurement ar ea is easily modified using in-line handrail connectors to change supp ort frame dimensions, thus accommodating infiltration and chemical or sediment transport studies.