angle between V and u in rotating machinery, measured between their positive directions; angle of bed slope to a horizontal datum line

angle between v and u in rotating machinery, measured between + v and ? u; Mach angle

height of surface roughness

any angle

absolute or dynamic viscosity, cP

kinematic viscosity ( ?/ ?),ft ²/s

density ( w/g)

surface tension, lb/ft

shear stress, lb/ft ²

any area, ft ²

cross-sectional area of a stream normal to the velocity, ft ²

linear acceleration, ft/s ²

any width, ft

length of weir crest, ft

width of turbine runner or pump impeller at periphery

bed width of open channel, ft

any coefficient

Ch zy s coefficient

coefficient of contraction for orifices, tubes, and nozzles

coefficient of discharge for orifices, tubes, and nozzles

coefficient of velocity for orifices, tubes, and nozzles

average skin coefficient for total surface

wave or acoustic velocity (celerity), ft/s

specific heat, Btu/lb F

local skin-friction coefficient

specific heat at constant pressure, Btu/lb F

diameter of pipe, turbine runner, or pump impeller, ft

enthalpy ( I