Pipeng Toolbox : Water Culvert Manning Equation Calculators Blank User
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Water Open Channel Or Culvert Flow Rate From The Manning Equation

Calculate flowrate in circular or rectangular water channels using the Manning equation.

`Q = A (rh^2)/3 s^(1/2) / n `
`rh = A/P `

where :

Q = flow rate
A = cross section area
P = wetted perimeter
rh = hydraulic radius
s = channel slope
n = Manning friction factor

The channel is assumed to be either open, or partly full and at ambient pressure. The head loss equals the change in elevation. Channel roughness is accounted for using the Manning friction factor. The hydraulic radius is the ratio of channel cross section area over the wetted perimeter. Valves, tees and other pipe fittings should be included by adding a minor loss equivalent length to the pipeline length.

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Links : ±
CALCULATOR : Rectangular Water Channel Flowrate From Manning Equation [FREE]   ±

Calculate the flowrate in an open rectangular water channel from the slope and cross section area using the Manning equation.

The Manning roughness coefficient n accounts for friction losses. The hydraulic radius is equal to the cross section area divided by the wetted perimeter (w h/(w + 2h) for a rectangular channel). Use the goal seek option to calculate either the hydraulic slope or the water height from flowrate.

Tool Input

  • nfactype : Channel Roughness Type
    • nu : User Defined Channel Roughness Factor
  • stype : Channel Slope Type
    • su : User Defined Channel Slope
    • gu : User Defined 50
    • Δzu : User Defined Delta Elevation
  • ρ : Fluid Density
  • W : Channel Width
  • H : Channel Liquid Height
  • L : Channel Length

Tool Output

  • Δz : Delta Elevation
  • M : Mass Flowrate
  • Q : Volume Flowrate
  • V : Fluid Velocity
  • g : Channel Gradient
  • n : Manning Roughness Factor
  • r : Hydraulic Radius
  • s : Channel Slope (Δz/L)

CALCULATOR : Circular Water Channel Flowrate From Manning Equation [FREE]   ±

Calculate the flowrate in a circular or semi circular water channel from the slope and cross section area using the Manning equation.

The channel is assumed to be either open, or partly full. The Manning roughness coefficient n accounts for friction losses. The hydraulic radius is equal to the cross section area divided by the wetted perimeter. Use the goal seek option to calculate either the hydraulic slope or the water height from flowrate.

Tool Input

  • nfactype : Channel Roughness Type
    • nu : User Defined Channel Roughness Factor
  • stype : Channel Slope Type
    • su : User Defined Channel Slope
    • gu : User Defined 50
    • Δzu : User Defined Delta Elevation
  • ρ : Fluid Density
  • ID : Channel Inside Diameter
  • H : Channel Liquid Height
  • L : Channel Length

Tool Output

  • Δz : Delta Elevation
  • M : Mass Flowrate
  • Q : Volume Flowrate
  • V : Fluid Velocity
  • g : Channel Gradient
  • n : Manning Roughness Factor
  • r : Hydraulic Radius
  • s : Channel Slope (Δz/L)

CALCULATOR : Water Pipeline Sea Water Density And Viscosity From Temperature [FREE]   ±

Calculate seawater density and viscosity at atmospheric pressure from temperature, and practical salinity.

Seawater viscosity is calculated from fresh water viscosity using the equation from Sharqawy (2010). The fresh water viscosity is calculated from temperature and density using the IAPWS R12-08 industrial equations. Practical salinity = parts per thousand of dissolved solids (mainly salt). The absolute salinity is taken as 35.16504 / 35 times the practical salinity. The absolute salinity anomaly δSA is ignored.

Tool Input

  • T : Seawater Temperature

Tool Output

  • μ : Dynamic Viscosity
  • ν : Kinematic Viscosity
  • ρ : Seawater Density

CALCULATOR : Water Pipeline Fresh Water Density And Viscosity From Temperature [FREE]   ±

Calculate fresh water density and viscosity from temperature at atmospheric pressure (IAPWS R12-08 and IAPWS R7-97 steam table).

The calculation is valid from 0 to 100 degrees C. Use the Result Plot option to plot viscosity versus temperature.

Tool Input

  • T : Temperature

Tool Output

  • μ : Dynamic Viscosity
  • ν : Kinematic Viscosity
  • ρ : Density