Rain Simulators

Abstract

There are two rainfall simulator systems: spray nozzles (including rotating sprays) and drip‐screens. Spray systems generally supply rainfall in pulses to the ground, and rotating sprays deliver rainfall across a large surface area although intensity usually decreases with distance from the rotating nozzle. The spray‐type systems often provide rainfall at terminal velocities which approach that of natural rainfall. Drip systems use hypodermic syringes or other drop formers across a fixed grid to produce rainfall across relatively small surface areas. The drop formers are often not raised high enough to allow representative terminal velocities, but they generally allow a constant rainfall rate whose drop sizes are more easily controlled than in the spray systems.