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Energy Slope is at a distance equal to the velocity head above the hydraulic gradient. Check FAQs
Sf=(nvm,R)2RH43
Sf - Energy Slope?n - Manning’s Roughness Coefficient?vm,R - Mean Velocity for Varied Flow?RH - Hydraulic Radius of Channel?

Manning's Formula for Energy Slope Example

With values
With units
Only example

Here is how the Manning's Formula for Energy Slope equation looks like with Values.

Here is how the Manning's Formula for Energy Slope equation looks like with Units.

Here is how the Manning's Formula for Energy Slope equation looks like.

0.243Edit=(0.012Edit56.2Edit)21.6Edit43
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Manning's Formula for Energy Slope Solution

Follow our step by step solution on how to calculate Manning's Formula for Energy Slope?

FIRST Step Consider the formula
Sf=(nvm,R)2RH43
Next Step Substitute values of Variables
Sf=(0.01256.2m/s)21.6m43
Next Step Prepare to Evaluate
Sf=(0.01256.2)21.643
Next Step Evaluate
Sf=0.24303853930597
LAST Step Rounding Answer
Sf=0.243

Manning's Formula for Energy Slope Formula Elements

Variables
Energy Slope
Energy Slope is at a distance equal to the velocity head above the hydraulic gradient.
Symbol: Sf
Measurement: NAUnit: Unitless
Note: Value should be greater than 0.
Manning’s Roughness Coefficient
Manning’s Roughness Coefficient represents the roughness or friction applied to the flow by the channel.
Symbol: n
Measurement: NAUnit: Unitless
Note: Value should be greater than 0.
Mean Velocity for Varied Flow
Mean velocity for Varied Flow is defined as the average velocity of a fluid at a point and over an arbitrary time T.
Symbol: vm,R
Measurement: SpeedUnit: m/s
Note: Value should be greater than 0.
Hydraulic Radius of Channel
Hydraulic Radius of Channel is the ratio of the cross-sectional area of a channel or pipe in which a fluid is flowing to the wet perimeter of the conduit.
Symbol: RH
Measurement: LengthUnit: m
Note: Value should be greater than 0.

Other Formulas to find Energy Slope

​Go Chezy Formula for Energy Slope
Sf=(vm,RCVF)2RH

Other formulas in Integration of the Varied Flow Equation category

​Go Manning's Formula for Roughness Coefficient given Energy Slope
n=(Sf(vm,R)2RH43)12
​Go Manning's Formula for Hydraulic Radius given Energy Slope
RH=((nvm,R)2Sf)34
​Go Manning's Formula for Mean Velocity given Energy Slope
vm,R=(Sf(n)2RH43)12
​Go Chezy Formula for Mean Velocity given Energy Slope
vm,R=Sf(CVF2)RH

How to Evaluate Manning's Formula for Energy Slope?

Manning's Formula for Energy Slope evaluator uses Energy Slope = ((Manning’s Roughness Coefficient*Mean Velocity for Varied Flow)^2)/(Hydraulic Radius of Channel^(4/3)) to evaluate the Energy Slope, The Manning's Formula for Energy Slope is defined as the channel energy slope in the section at any point. Energy Slope is denoted by Sf symbol.

How to evaluate Manning's Formula for Energy Slope using this online evaluator? To use this online evaluator for Manning's Formula for Energy Slope, enter Manning’s Roughness Coefficient (n), Mean Velocity for Varied Flow (vm,R) & Hydraulic Radius of Channel (RH) and hit the calculate button.

FAQs on Manning's Formula for Energy Slope

What is the formula to find Manning's Formula for Energy Slope?
The formula of Manning's Formula for Energy Slope is expressed as Energy Slope = ((Manning’s Roughness Coefficient*Mean Velocity for Varied Flow)^2)/(Hydraulic Radius of Channel^(4/3)). Here is an example- 0.243039 = ((0.012*56.2)^2)/(1.6^(4/3)).
How to calculate Manning's Formula for Energy Slope?
With Manning’s Roughness Coefficient (n), Mean Velocity for Varied Flow (vm,R) & Hydraulic Radius of Channel (RH) we can find Manning's Formula for Energy Slope using the formula - Energy Slope = ((Manning’s Roughness Coefficient*Mean Velocity for Varied Flow)^2)/(Hydraulic Radius of Channel^(4/3)).
What are the other ways to Calculate Energy Slope?
Here are the different ways to Calculate Energy Slope-
  • Energy Slope=((Mean Velocity for Varied Flow/Chézy’s Coefficients for Varied Flow)^2)/Hydraulic Radius of ChannelOpenImg
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