In axial flow turbines, u_o = u_i = 0.15 to 0.2 [root](2gH);
In outward flow turbines, u_i = 0.25 [root]2g(H - [h]),
u_o = 0.21 to 0.17 [root]2g(H - [h]);
In inward flow turbines, u_o = u_i = 0.125 [root](2gH).
§ 191. _Speed of the Wheel._--The best speed of the wheel depends
partly on the frictional losses, which the ordinary theory of turbines
disregards. It is best, therefore, to assume for V_o and V_i values
which experiment has shown to be most advantageous.
In axial flow turbines, the circumferential velocities at the mean
radius of the wheel may be taken
V_o = V_i = 0.6 [root](2gH) to 0.66 [root](2gH).
In a radial outward flow turbine,