Wetted Perimeter from Manning's Law Calculator

✖Manning’s Roughness Coefficient represents the roughness or friction applied to the flow by the channel.ⓘ Manning’s Roughness Coefficient [n]			+10% -10%
✖Cross-Sectional Area is the area of a two-dimensional shape that is obtained when a three-dimensional shape is sliced perpendicular to some specified axis at a point.ⓘ Cross-Sectional Area [A]			+10% -10%
✖Conveyance Function on stage at a section may be determined empirically or by a standard friction law.ⓘ Conveyance Function [K]			+10% -10%

✖Wetted Perimeter is defined as the surface of the channel bottom and sides in direct contact with the aqueous body.ⓘ Wetted Perimeter from Manning's Law [P]

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Formula

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Wetted Perimeter from Manning's Law

Formula

`"P" = ((1/"n")*("A"^(5/3)/"K"))^(3/2)`

Example

`"83.3628m"=((1/"0.412")*(("12.0m²")^(5/3)/"8"))^(3/2)`

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Wetted Perimeter from Manning's Law Solution

STEP 0: Pre-Calculation Summary

Formula Used

Wetted Perimeter = ((1/Manning’s Roughness Coefficient)*(Cross-Sectional Area^(5/3)/Conveyance Function))^(3/2)
P = ((1/n)*(A^(5/3)/K))^(3/2)
This formula uses 4 Variables

Variables Used

Wetted Perimeter - (Measured in Meter) - Wetted Perimeter is defined as the surface of the channel bottom and sides in direct contact with the aqueous body.
Manning’s Roughness Coefficient - Manning’s Roughness Coefficient represents the roughness or friction applied to the flow by the channel.
Cross-Sectional Area - (Measured in Square Meter) - Cross-Sectional Area is the area of a two-dimensional shape that is obtained when a three-dimensional shape is sliced perpendicular to some specified axis at a point.
Conveyance Function - Conveyance Function on stage at a section may be determined empirically or by a standard friction law.

STEP 1: Convert Input(s) to Base Unit

Manning’s Roughness Coefficient: 0.412 --> No Conversion Required
Cross-Sectional Area: 12 Square Meter --> 12 Square Meter No Conversion Required
Conveyance Function: 8 --> No Conversion Required

STEP 2: Evaluate Formula

Substituting Input Values in Formula

P = ((1/n)*(A^(5/3)/K))^(3/2) --> ((1/0.412)*(12^(5/3)/8))^(3/2)

Evaluating ... ...

P = 83.3628033100679

STEP 3: Convert Result to Output's Unit

83.3628033100679 Meter --> No Conversion Required

FINAL ANSWER

83.3628033100679 ≈ 83.3628 Meter <-- Wetted Perimeter

(Calculation completed in 00.004 seconds)

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Conveyance Function Determined by Manning's Law

Go Conveyance Function = (1/Manning’s Roughness Coefficient)*(Cross-Sectional Area)^(5/3)/(Wetted Perimeter)^(2/3)

Wetted Perimeter from Manning's Law

Go Wetted Perimeter = ((1/Manning’s Roughness Coefficient)*(Cross-Sectional Area^(5/3)/Conveyance Function))^(3/2)

Cross-sectional Area using Manning's Law

Go Cross-Sectional Area = (Conveyance Function*Manning’s Roughness Coefficient*Wetted Perimeter^(2/3))^(3/5)

Cross-sectional Area using Chezy's Law

Go Cross-Sectional Area = ((Conveyance Function*Wetted Perimeter^(1/2))/Chézy’s Coefficients)^(2/3)

Conveyance Function determined by Chezy's Law

Go Conveyance Function = Chézy’s Coefficients*(Cross-Sectional Area^(3/2)/Wetted Perimeter^(1/2))

Wetted Perimeter using Chezy's Law

Go Wetted Perimeter = (Chézy’s Coefficients*(Cross-Sectional Area^(3/2)/Conveyance Function))^2

Instantaneous Discharge given Friction Slope

Go Instantaneous Discharge = sqrt(Friction Slope*Conveyance Function^2)

Friction Slope

Go Friction Slope = Instantaneous Discharge^2/Conveyance Function^2

Wetted Perimeter from Manning's Law Formula

Wetted Perimeter = ((1/Manning’s Roughness Coefficient)*(Cross-Sectional Area^(5/3)/Conveyance Function))^(3/2)
P = ((1/n)*(A^(5/3)/K))^(3/2)

What is Manning’s Law?

The Manning equation is an empirical equation that describes the relationship between the velocity in a conduit and the channel geometry, slope, and a friction coefficient expressed as a Manning n.

Description about Manning's Law.

Even though Manning’s law was originally intended for flow which is both steady (unchanging in time) and uniform (unchanging along the waterway), they have been widely accepted as the governing friction equations in more generally unsteady and non-uniform flows.

How to Calculate Wetted Perimeter from Manning's Law?

Wetted Perimeter from Manning's Law calculator uses Wetted Perimeter = ((1/Manning’s Roughness Coefficient)*(Cross-Sectional Area^(5/3)/Conveyance Function))^(3/2) to calculate the Wetted Perimeter, The Wetted Perimeter from Manning's Law formula is an empirical equation describing the relationship between the velocity in a conduit and the channel geometry, slope, and friction coefficient expressed as a Manning n. Wetted Perimeter is denoted by P symbol.

How to calculate Wetted Perimeter from Manning's Law using this online calculator? To use this online calculator for Wetted Perimeter from Manning's Law, enter Manning’s Roughness Coefficient (n), Cross-Sectional Area (A) & Conveyance Function (K) and hit the calculate button. Here is how the Wetted Perimeter from Manning's Law calculation can be explained with given input values -> 83.3628 = ((1/0.412)*(12^(5/3)/8))^(3/2).

FAQ

What is Wetted Perimeter from Manning's Law?

The Wetted Perimeter from Manning's Law formula is an empirical equation describing the relationship between the velocity in a conduit and the channel geometry, slope, and friction coefficient expressed as a Manning n and is represented as P = ((1/n)*(A^(5/3)/K))^(3/2) or Wetted Perimeter = ((1/Manning’s Roughness Coefficient)*(Cross-Sectional Area^(5/3)/Conveyance Function))^(3/2). Manning’s Roughness Coefficient represents the roughness or friction applied to the flow by the channel, Cross-Sectional Area is the area of a two-dimensional shape that is obtained when a three-dimensional shape is sliced perpendicular to some specified axis at a point & Conveyance Function on stage at a section may be determined empirically or by a standard friction law.

How to calculate Wetted Perimeter from Manning's Law?

The Wetted Perimeter from Manning's Law formula is an empirical equation describing the relationship between the velocity in a conduit and the channel geometry, slope, and friction coefficient expressed as a Manning n is calculated using Wetted Perimeter = ((1/Manning’s Roughness Coefficient)*(Cross-Sectional Area^(5/3)/Conveyance Function))^(3/2). To calculate Wetted Perimeter from Manning's Law, you need Manning’s Roughness Coefficient (n), Cross-Sectional Area (A) & Conveyance Function (K). With our tool, you need to enter the respective value for Manning’s Roughness Coefficient, Cross-Sectional Area & Conveyance Function and hit the calculate button. You can also select the units (if any) for Input(s) and the Output as well.

How many ways are there to calculate Wetted Perimeter?

In this formula, Wetted Perimeter uses Manning’s Roughness Coefficient, Cross-Sectional Area & Conveyance Function. We can use 1 other way(s) to calculate the same, which is/are as follows -

Wetted Perimeter = (Chézy’s Coefficients*(Cross-Sectional Area^(3/2)/Conveyance Function))^2

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