# Fluid Mechanics - Imperial and SI Units Dimensions

## Imperial (USCS) and SI dimensions and units terminology in fluid mechanics

Fluid mechanics in the

• Imperial or USCS - United States Customary Units
• International System of Units - SI system
TerminologyDimensionsImperial Units
(USCS)
SI-units
Acceleration due to gravity L / T2 ft/s2 m/s2
Area L2 ft2 m2
Chezy roughness coefficient L1/2 / T ft1/2/s m1/2/s
Critical Depth L ft m
Density F T2 / L4 lb s2/ ft4
N s2/m4
Depth L ft m
Depth in open channel L ft m
Diameter L ft m
Distance from solid boundary L ft m
Flow rate L3 / T ft3/s m3/s
Force F lb N
Force due to pressure F lb N
Hazen Williams roughness coefficient L0.37 / T ft0.37/s m0.37/s
Head loss due to friction L ft m
Head of height L ft m
Head of weir L ft m
Height above datum L ft m
Kinematic viscosity L2 / T ft2/s m2/s
Length L ft m
Manning's roughness coefficient T / L1/3 s/ft1/3 s/m1/3
Mass F T2 / L lb s2/ft N s2/m
Modulus of elasticity F / L2 lb/in2 (psi) Pa
Perimeter, Weir Height L ft m
Pressure F / L2 lb/ft2 Pa
Shear stress F / L2 lb/ft2 Pa
Size of roughness L ft m
Specific weight F / L3 lb/ft3 kg/m3
Surface tension F / L lb/ft kg/m
Time T s s
Thickness L ft m
Time T s s
Unit flow rate L3 / T L ft3/(s ft) m3/(s ft)
Velocity L / T ft/s m/s
Viscosity F T / L2 lb s/ft Pa s
Weight F lbf N
• L - length
• F - force
• T - time

## Related Topics

• Fluid Mechanics - The study of fluids - liquids and gases. Involves velocity, pressure, density and temperature as functions of space and time

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