Resistance Coefficient ( Ke ) For Entrance

Inward projecting----Sharp edged---Slightly Rounded---Well Rounded

he = Ke * V₂ ² / (2*g)

he = Entrance losses (m)
Ke = Depends upon the shape of the intake opening
V2 = The average velocity (m/s) of water in penstock
g = Gravitational constant (9.8 m/s^2)

Ref :
ESHA (European Small Hydropower Association),”Layman’s Handbook on How To Develop a Small Hydro Site,”2nd ed, 1998 http://www.scribd.com/doc/8885765/Layman-Handbook-for-hydro-electric-power-plants