Abstract
1. On the revolution of Arm-type sprinkler head, by which jet angle and revolving speed of sprinkler and jet are variable, direction angle θ or jet angle λ is a function of adjustable angle δ.
H is given by equation (5) and λ by (6).
2. The torque T caused by sprinkler jet stream is derived as a function of jet velocity v, and δ, θ, λ. Friction torque TB is given by eq. (9), considering Coreori's Force TR.
When the Head continues constant speed, the angular speed ω is given by eq. (10).
When ω=0 the initial torque TB=T is measured and calculated at jet angles λ=0°, 30°, 60°, 90°, and 5 levels of water pressure.
Compared Rainbird's head No. 30 with Arm type head, the torque of both heads is nearly equal at the range λ=27°-70°, and Arm-type head revolves round smoothly and nicely in these conditions.
