wo = vo cos β; uo = vo sin β
wi = vi cos α; ui = vi sin α.
(10)
The velocities of flow are easily ascertained independently from the dimensions of the wheel. The velocities of flow at the inlet and outlet surfaces of the wheel are normal to those surfaces. Let Ωo, Ωi be the areas of the outlet and inlet surfaces of the wheel, and Q the volume of water passing through the wheel per second; then
v0 = Q/Ωo; vi = Q/Ωi.
(11)
Using the notation in fig. 191, we have, for an inward flow turbine (neglecting the space occupied by the vanes),
Ωo = 2πr0d0; Ωi = 2πridi.
(12a)
Similarly, for an outward flow turbine,
Ωo = 2πrod; Ωi = 2πrid;