Length of Crest if Critical Depth is Constant for Discharge of Weir Calculator

✖Discharge Over Broad Crested Weir is a measure of the quantity of any fluid flow over unit time. The quantity may be either volume or mass.ⓘ Discharge Over Broad Crested Weir [Q_w]			+10% -10%
✖Coefficient of Discharge is ratio of Actual discharge to theoretical discharge.ⓘ Coefficient of Discharge [C_d]			+10% -10%
✖Total Head is the combination of weir crested and additional head.ⓘ Total Head [H]			+10% -10%

✖Length of Weir Crest is the measurement or extent of Weir Crest from end to end.ⓘ Length of Crest if Critical Depth is Constant for Discharge of Weir [L_w]

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Formula

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Length of Crest if Critical Depth is Constant for Discharge of Weir

Formula

`"L"_{"w"} = "Q"_{"w"}/(1.70*"C"_{"d"}*("H")^(3/2))`

Example

`"2.120478m"="26.6m³/s"/(1.70*"0.66"*("5m")^(3/2))`

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Length of Crest if Critical Depth is Constant for Discharge of Weir Solution

STEP 0: Pre-Calculation Summary

Formula Used

Length of Weir Crest = Discharge Over Broad Crested Weir/(1.70*Coefficient of Discharge*(Total Head)^(3/2))
L_w = Q_w/(1.70*C_d*(H)^(3/2))
This formula uses 4 Variables

Variables Used

Length of Weir Crest - (Measured in Meter) - Length of Weir Crest is the measurement or extent of Weir Crest from end to end.
Discharge Over Broad Crested Weir - (Measured in Cubic Meter per Second) - Discharge Over Broad Crested Weir is a measure of the quantity of any fluid flow over unit time. The quantity may be either volume or mass.
Coefficient of Discharge - Coefficient of Discharge is ratio of Actual discharge to theoretical discharge.
Total Head - (Measured in Meter) - Total Head is the combination of weir crested and additional head.

STEP 1: Convert Input(s) to Base Unit

Discharge Over Broad Crested Weir: 26.6 Cubic Meter per Second --> 26.6 Cubic Meter per Second No Conversion Required
Coefficient of Discharge: 0.66 --> No Conversion Required
Total Head: 5 Meter --> 5 Meter No Conversion Required

STEP 2: Evaluate Formula

Substituting Input Values in Formula

L_w = Q_w/(1.70*C_d*(H)^(3/2)) --> 26.6/(1.70*0.66*(5)^(3/2))

Evaluating ... ...

L_w = 2.12047801074846

STEP 3: Convert Result to Output's Unit

2.12047801074846 Meter --> No Conversion Required

FINAL ANSWER

2.12047801074846 ≈ 2.120478 Meter <-- Length of Weir Crest

(Calculation completed in 00.004 seconds)

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Home » Engineering » Civil » Hydraulics and Waterworks » Flow Over Notches and Weirs » Broad Crested Weir » Length of Crest if Critical Depth is Constant for Discharge of Weir

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< 20 Broad Crested Weir Calculators

Coefficient of Discharge given Actual Discharge over Broad Crested Weir

Go Coefficient of Discharge = Actual Discharge over Broad Crested Weir/(Length of Weir Crest*Critical Depth of Weir*sqrt((2*Acceleration due to Gravity)*(Total Head-Critical Depth of Weir)))

Length of Crest given Actual Discharge over Broad Crested Weir

Go Length of Weir Crest = Actual Discharge over Broad Crested Weir/(Coefficient of Discharge*Critical Depth of Weir*sqrt((2*Acceleration due to Gravity)*(Total Head-Critical Depth of Weir)))

Actual Discharge over Broad Crested Weir

Go Actual Discharge over Broad Crested Weir = Coefficient of Discharge*Length of Weir Crest*Critical Depth of Weir*sqrt((2*Acceleration due to Gravity)*(Total Head-Critical Depth of Weir))

Total Head for Actual Discharge over Broad Crested Weir

Go Total Head = (((Actual Discharge over Broad Crested Weir/(Coefficient of Discharge*Length of Weir Crest*Critical Depth of Weir))^2)*(1/(2*Acceleration due to Gravity)))+Critical Depth of Weir

Length of Crest given Discharge over Weir

Go Length of Weir Crest = Discharge Over Broad Crested Weir/(Critical Depth of Weir*sqrt((2*[g])*(Total Head-Critical Depth of Weir)))

Discharge over Broad Crested Weir

Go Discharge Over Broad Crested Weir = Length of Weir Crest*Critical Depth of Weir*sqrt((2*[g])*(Total Head-Critical Depth of Weir))

Total Head given Discharge over Weir Crest

Go Total Head = ((Discharge Over Broad Crested Weir/(Length of Weir Crest*Critical Depth of Weir))^2)*(1/(2*[g]))+Critical Depth of Weir

Velocity of Flow given Head

Go Velocity of Fluid for Weir = sqrt((2*Acceleration due to Gravity)*(Total Head-Critical Depth of Weir))

Head if Velocity is considered for Discharge over Broad Crested Weir

Go Total Head = (Max Discharge Over Broad Crested Weir/(1.70*Coefficient of Discharge*Length of Weir Crest))^(2/3)

Coefficient of Discharge for Max Discharge over Crested Weir

Go Coefficient of Discharge = Max Discharge Over Broad Crested Weir/(1.70*Length of Weir Crest*(Total Head)^(3/2))

Length of Crest over Broad Crested Weir for Max Discharge

Go Length of Weir Crest = Max Discharge Over Broad Crested Weir/(1.70*Coefficient of Discharge*(Total Head)^(3/2))

Total Head for Maximum Discharge

Go Total Head = (Max Discharge Over Broad Crested Weir/(1.70*Coefficient of Discharge*Length of Weir Crest))^(2/3)

Maximum Discharge of Broad Crested Weir if Critical Depth is Constant

Go Max Discharge Over Broad Crested Weir = 1.70*Coefficient of Discharge*Length of Weir Crest*(Total Head)^(3/2)

Max Discharge over Broad Crested Weir

Go Max Discharge Over Broad Crested Weir = 1.70*Coefficient of Discharge*Length of Weir Crest*(Total Head)^(3/2)

Coefficient of Discharge given Discharge of Weir if Critical Depth is Constant

Go Coefficient of Discharge = Discharge Over Broad Crested Weir/(1.70*Length of Weir Crest*(Total Head)^(3/2))

Length of Crest if Critical Depth is Constant for Discharge of Weir

Go Length of Weir Crest = Discharge Over Broad Crested Weir/(1.70*Coefficient of Discharge*(Total Head)^(3/2))

Critical Depth due to Reduction in Area of Flow Section given Total Head

Go Critical Depth of Weir = Total Head-(Velocity of Fluid for Weir^2/(2*Acceleration due to Gravity))

Total Head above Weir Crest

Go Total Head = Critical Depth of Weir+(Velocity of Fluid for Weir^2/(2*Acceleration due to Gravity))

Head for Broad Crested Weir

Go Head on Upstream of Weir = (Total Head+Additional Head)

Additional Head given Head for Broad Crested Weir

Go Additional Head = Head on Upstream of Weir-Total Head

Length of Crest if Critical Depth is Constant for Discharge of Weir Formula

Length of Weir Crest = Discharge Over Broad Crested Weir/(1.70*Coefficient of Discharge*(Total Head)^(3/2))
L_w = Q_w/(1.70*C_d*(H)^(3/2))

What does Coefficien of Discharge mean?

Coefficient of Discharge is stated as the ratio between the actual flow discharge and theoretical flow discharge.

What is a Weir?

A weir or low head dam is a barrier across the width of a river that alters the flow characteristics of water and usually results in a change in the height of the river level. They are also used to control the flow of water for outlets of lakes, ponds, and reservoirs.

How to Calculate Length of Crest if Critical Depth is Constant for Discharge of Weir?

Length of Crest if Critical Depth is Constant for Discharge of Weir calculator uses Length of Weir Crest = Discharge Over Broad Crested Weir/(1.70*Coefficient of Discharge*(Total Head)^(3/2)) to calculate the Length of Weir Crest, Length of Crest if Critical Depth is Constant for Discharge of Weir is defined as the depth of flow at maximum discharge capacity, is maintained. Length of Weir Crest is denoted by L_w symbol.

How to calculate Length of Crest if Critical Depth is Constant for Discharge of Weir using this online calculator? To use this online calculator for Length of Crest if Critical Depth is Constant for Discharge of Weir, enter Discharge Over Broad Crested Weir (Q_w), Coefficient of Discharge (C_d) & Total Head (H) and hit the calculate button. Here is how the Length of Crest if Critical Depth is Constant for Discharge of Weir calculation can be explained with given input values -> 2.120478 = 26.6/(1.70*0.66*(5)^(3/2)).

FAQ

What is Length of Crest if Critical Depth is Constant for Discharge of Weir?

Length of Crest if Critical Depth is Constant for Discharge of Weir is defined as the depth of flow at maximum discharge capacity, is maintained and is represented as L_w = Q_w/(1.70*C_d*(H)^(3/2)) or Length of Weir Crest = Discharge Over Broad Crested Weir/(1.70*Coefficient of Discharge*(Total Head)^(3/2)). Discharge Over Broad Crested Weir is a measure of the quantity of any fluid flow over unit time. The quantity may be either volume or mass, Coefficient of Discharge is ratio of Actual discharge to theoretical discharge & Total Head is the combination of weir crested and additional head.

How to calculate Length of Crest if Critical Depth is Constant for Discharge of Weir?

Length of Crest if Critical Depth is Constant for Discharge of Weir is defined as the depth of flow at maximum discharge capacity, is maintained is calculated using Length of Weir Crest = Discharge Over Broad Crested Weir/(1.70*Coefficient of Discharge*(Total Head)^(3/2)). To calculate Length of Crest if Critical Depth is Constant for Discharge of Weir, you need Discharge Over Broad Crested Weir (Q_w), Coefficient of Discharge (C_d) & Total Head (H). With our tool, you need to enter the respective value for Discharge Over Broad Crested Weir, Coefficient of Discharge & Total Head 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 Length of Weir Crest?

In this formula, Length of Weir Crest uses Discharge Over Broad Crested Weir, Coefficient of Discharge & Total Head. We can use 3 other way(s) to calculate the same, which is/are as follows -

Length of Weir Crest = Discharge Over Broad Crested Weir/(Critical Depth of Weir*sqrt((2*[g])*(Total Head-Critical Depth of Weir)))
Length of Weir Crest = Actual Discharge over Broad Crested Weir/(Coefficient of Discharge*Critical Depth of Weir*sqrt((2*Acceleration due to Gravity)*(Total Head-Critical Depth of Weir)))
Length of Weir Crest = Max Discharge Over Broad Crested Weir/(1.70*Coefficient of Discharge*(Total Head)^(3/2))

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