Drop and Energy Characteristics of a Rotating Spray-Plate Sprinkler

A laboratory investigation was conducted to measure wetted radii and drop sizes and to estimate the energy characteristics of a rotating spray-plate sprinkler. Maximum wetted radii were positively related to increasing sprinkler elevation above an irrigated surface and increasing nozzle pressure. Nozzle diameter had a minimal effect on drop size, but nozzle pressure had a significant inverse influence. Energy parameters were calculated for sprinkler operational scenarios. Average kinetic energies over sprinkler-wetted areas were inversely related to nozzle pressure and the square of nozzle pressure. Rapidly and slowly rotating spray plate sprinklers had similar time-averaged specific power distributions. However, the rapidly rotating sprinklers had continuous rotational distribution patterns in space with relatively low peak specific power values that corresponded to natural rainfall intensities of about 20 mm/h. Slowly rotating sprinklers had discontinuous spatial distribution patterns with very high peak values that corresponded to natural rainfall intensities of about 200 mm/h.