The Manning's roughness coefficient is used in the Manning's equation to calculate flow in open channels.
Coefficients for some commonly used surface materials:
|Surface Material||Manning's Roughness|
- n -
|Brick and cement mortar sewers||0.015|
|Cast or Ductile iron, new||0.012|
|Concrete - steel forms||0.011|
|Concrete (Cement) - finished||0.012|
|Concrete - wooden forms||0.015|
|Concrete - centrifugally spun||0.013|
|Earth channel - clean||0.022|
|Earth channel - gravelly||0.025|
|Earth channel - weedy||0.030|
|Earth channel - stony, cobbles||0.035|
|Floodplains - pasture, farmland||0.035|
|Floodplains - light brush||0.050|
|Floodplains - heavy brush||0.075|
|Floodplains - trees||0.15|
|Metal - corrugated||0.022|
|Natural streams - clean and straight||0.030|
|Natural streams - major rivers||0.035|
|Natural streams - sluggish with deep pools||0.040|
|Natural channels, very poor condition||0.060|
|Polyethylene PE - Corrugated with smooth inner walls||0.009 - 0.015|
|Polyethylene PE - Corrugated with corrugated inner walls||0.018 - 0.025|
|Polyvinyl Chloride PVC - with smooth inner walls||0.009 - 0.011|
|Rubble Masonry||0.017 - 0.022|
|Steel - Coal-tar enamel||0.010|
|Steel - smooth||0.012|
|Steel - New unlined||0.011|
|Steel - Riveted||0.019|
|Vitrified clay sewer pipe||0.013 - 0.015|
|Wood - planed||0.012|
|Wood - unplaned||0.013|
|Wood stave pipe, small diameter||0.011 - 0.012|
|Wood stave pipe, large diameter||0.012 - 0.013|
The study of fluids - liquids and gases. Involving velocity, pressure, density and temperature as functions of space and time.
Dimensions of threaded ductile-iron pipe according AWWA C115.
Dimensions of ductile-iron pipes according AWWA C151/A.21.51.
Imperial (USCS) and SI dimensions and units terminology in fluid mechanics.
Comparing sandpaper grit size and surface roughness.
Calculate cross-sectional average velocity flow in open channels.
Surface coefficients that can be used to calculate friction and major pressure loss for fluid flow with surfaces like concrete, galvanized steel, corroded steel and more.
Grit sizes ranging 12 - 600.
U.S. mesh size vs. surface roughness.
Mechanical production methods and their surface roughness.