Cross-sectional Area using Manning's Law Calculator

✖Conveyance Function on stage at a section may be determined empirically or by a standard friction law.ⓘ Conveyance Function [K]			+10% -10%
✖Manning’s Roughness Coefficient represents the roughness or friction applied to the flow by the channel.ⓘ Manning’s Roughness Coefficient [n]			+10% -10%
✖Wetted Perimeter is defined as the surface of the channel bottom and sides in direct contact with the aqueous body.ⓘ Wetted Perimeter [P]			+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 using Manning's Law [A]

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Formula

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Cross-sectional Area using Manning's Law

Formula

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

Example

`"11.80398m²"=("8"*"0.412"*("80m")^(2/3))^(3/5)`

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Cross-sectional Area using Manning's Law Solution

STEP 0: Pre-Calculation Summary

Formula Used

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

Variables Used

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.
Manning’s Roughness Coefficient - Manning’s Roughness Coefficient represents the roughness or friction applied to the flow by the channel.
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.

STEP 1: Convert Input(s) to Base Unit

Conveyance Function: 8 --> No Conversion Required
Manning’s Roughness Coefficient: 0.412 --> No Conversion Required
Wetted Perimeter: 80 Meter --> 80 Meter No Conversion Required

STEP 2: Evaluate Formula

Substituting Input Values in Formula

A = (K*n*P^(2/3))^(3/5) --> (8*0.412*80^(2/3))^(3/5)

Evaluating ... ...

A = 11.8039759672834

STEP 3: Convert Result to Output's Unit

11.8039759672834 Square Meter --> No Conversion Required

FINAL ANSWER

11.8039759672834 ≈ 11.80398 Square Meter <-- Cross-Sectional Area

(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

Cross-sectional Area using Manning's Law Formula

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

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 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 Cross-sectional Area using Manning's Law?

Cross-sectional Area using Manning's Law calculator uses Cross-Sectional Area = (Conveyance Function*Manning’s Roughness Coefficient*Wetted Perimeter^(2/3))^(3/5) to calculate the Cross-Sectional Area, The Cross-sectional Area using Manning's Law formula is defined as the area of flow calculated as the product of the conveyance function, manning's coefficient and wetted perimeter. Cross-Sectional Area is denoted by A symbol.

How to calculate Cross-sectional Area using Manning's Law using this online calculator? To use this online calculator for Cross-sectional Area using Manning's Law, enter Conveyance Function (K), Manning’s Roughness Coefficient (n) & Wetted Perimeter (P) and hit the calculate button. Here is how the Cross-sectional Area using Manning's Law calculation can be explained with given input values -> 11.80398 = (8*0.412*80^(2/3))^(3/5).

FAQ

What is Cross-sectional Area using Manning's Law?

The Cross-sectional Area using Manning's Law formula is defined as the area of flow calculated as the product of the conveyance function, manning's coefficient and wetted perimeter and is represented as A = (K*n*P^(2/3))^(3/5) or Cross-Sectional Area = (Conveyance Function*Manning’s Roughness Coefficient*Wetted Perimeter^(2/3))^(3/5). Conveyance Function on stage at a section may be determined empirically or by a standard friction law, Manning’s Roughness Coefficient represents the roughness or friction applied to the flow by the channel & Wetted Perimeter is defined as the surface of the channel bottom and sides in direct contact with the aqueous body.

How to calculate Cross-sectional Area using Manning's Law?

The Cross-sectional Area using Manning's Law formula is defined as the area of flow calculated as the product of the conveyance function, manning's coefficient and wetted perimeter is calculated using Cross-Sectional Area = (Conveyance Function*Manning’s Roughness Coefficient*Wetted Perimeter^(2/3))^(3/5). To calculate Cross-sectional Area using Manning's Law, you need Conveyance Function (K), Manning’s Roughness Coefficient (n) & Wetted Perimeter (P). With our tool, you need to enter the respective value for Conveyance Function, Manning’s Roughness Coefficient & Wetted Perimeter 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 Cross-Sectional Area?

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

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

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