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# Fluid Mechanics - Imperial and SI Units vs. 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
Fluid Mechanics - Imperial and SI Units vs. Dimensions
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. Involving velocity, pressure, density and temperature as functions of space and time.

## Related Documents

• ### Chezys Conduit Flow Equation

Calculating volume flow and velcity in open conduits.
• ### Fluid Flow Friction Loss - Hazen-Williams Coefficients

Hazen-Williams friction loss coefficients for commonly used piping materials.
• ### Manning's Roughness Coefficients

Manning's roughness coefficients for some common materials.
• ### SI System

An introduction to the SI metric system.
• ### Symbols Used to Denote a Chemical Reactions and Process or Condition

Explanation of symbols used as subscripts or superscripts to tell more about the type of chemical reaction, process or condition.
• ### Unit Converter with commonly used Units

Common converting units for Acceleration, Area, Density, Energy, Energy per unit mass, Force, Heat flow rate, Heat flux, Heat generation per unit volume and many more.
• ### USCS - United States Customary System Units

An overview of the United States Customary System Units - Imperial Units.
• ### Volume Flow - Online Unit Converter

Convert between volume flow units like gpm, liter/sec, cfm, m3/h.

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## Citation

• The Engineering ToolBox (2005). Fluid Mechanics - Imperial and SI Units vs. Dimensions. [online] Available at: https://www.engineeringtoolbox.com/terminology-units-d_963.html [Accessed Day Month Year].

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8.21.8

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