PROBLEM FORMULATION
Fig. 5 is a profile view of a segment of an Archimedes screw
showing how the buckets are formed between pairs of adjacent
blades. The buckets move up the screw as it is rotated clockwise
when viewed from the upper reservoir. (Throughout this
paper the screws are oriented for clockwise rotation). The inner
and outer edges of each blade determine two sinusoidal
curves of the same period (or pitch) and phase. One has an
amplitude equal to the inner radius of the screw and the other
has an amplitude equal to the outer radius. The angle u that
the screw makes with the horizontal determines its slope tan u.
Now defined are the following three ‘‘external’’ parameters:
Ro = radius of screw’s outer cylinder (m)
L = total length of screw (m)
K = slope of screw (dimensionless)