Length of Crest when Francis Formula Discharge and Velocity is considered Solution

STEP 0: Pre-Calculation Summary
Formula Used
Length of Weir Crest = (Francis Discharge/(1.84*(Still Water Head^(3/2)-Velocity Head^(3/2))))+(0.1*Number of End Contraction*Still Water Head)
Lw = (QFr/(1.84*(HStillwater^(3/2)-HV^(3/2))))+(0.1*n*HStillwater)
This formula uses 5 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.
Francis Discharge - (Measured in Cubic Meter per Second) - Francis Discharge is calculated from the empirical formula given by Francis.
Still Water Head - (Measured in Meter) - Still Water Head is the head of water which is still over weir.
Velocity Head - (Measured in Meter) - Velocity Head is represented in the term of length unit, also referred to as kinetic head represents the kinetic energy of the fluid.
Number of End Contraction - Number of End Contraction 1 can be described as the end contractions acting on a channel.
STEP 1: Convert Input(s) to Base Unit
Francis Discharge: 8 Cubic Meter per Second --> 8 Cubic Meter per Second No Conversion Required
Still Water Head: 6.6 Meter --> 6.6 Meter No Conversion Required
Velocity Head: 4.6 Meter --> 4.6 Meter No Conversion Required
Number of End Contraction: 4 --> No Conversion Required
STEP 2: Evaluate Formula
Substituting Input Values in Formula
Lw = (QFr/(1.84*(HStillwater^(3/2)-HV^(3/2))))+(0.1*n*HStillwater) --> (8/(1.84*(6.6^(3/2)-4.6^(3/2))))+(0.1*4*6.6)
Evaluating ... ...
Lw = 3.2532503492487
STEP 3: Convert Result to Output's Unit
3.2532503492487 Meter --> No Conversion Required
FINAL ANSWER
3.2532503492487 3.25325 Meter <-- Length of Weir Crest
(Calculation completed in 00.004 seconds)

Credits

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Created by M Naveen
National Institute of Technology (NIT), Warangal
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Coorg Institute of Technology (CIT), Coorg
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Length of Crest Calculators

Length of Crest considering Velocity
​ LaTeX ​ Go Length of Weir Crest = ((3*Francis Discharge with Suppressed End)/(2*Coefficient of Discharge*sqrt(2*Acceleration due to Gravity)*(Still Water Head^(3/2)-Velocity Head^(3/2))))+(0.1*Number of End Contraction*Still Water Head)
Length of Crest given Discharge Passing over Weir
​ LaTeX ​ Go Length of Weir Crest = (Francis Discharge with Suppressed End*3)/(2*Coefficient of Discharge*sqrt(2*Acceleration due to Gravity)*((Height of Water above Crest of Weir+Velocity Head)^(3/2)-Velocity Head^(3/2)))
Length of Crest without considering Velocity
​ LaTeX ​ Go Length of Weir Crest = ((Francis Discharge*2)/(3*Coefficient of Discharge*sqrt(2*Acceleration due to Gravity)))^(2/3)+(0.1*Number of End Contraction*Height of Water above Crest of Weir)
Length of Crest when Francis Formula Discharge and Velocity is not considered
​ LaTeX ​ Go Length of Weir Crest = (Francis Discharge/(1.84*Height of Water above Crest of Weir^(3/2)))+(0.1*Number of End Contraction*Height of Water above Crest of Weir)

Length of Crest when Francis Formula Discharge and Velocity is considered Formula

​LaTeX ​Go
Length of Weir Crest = (Francis Discharge/(1.84*(Still Water Head^(3/2)-Velocity Head^(3/2))))+(0.1*Number of End Contraction*Still Water Head)
Lw = (QFr/(1.84*(HStillwater^(3/2)-HV^(3/2))))+(0.1*n*HStillwater)

What is meant by Head?

In hydraulics, Head is a measure of the potential of fluid at the measurement point. or total energy per unit weight above a datum.

How to Calculate Length of Crest when Francis Formula Discharge and Velocity is considered?

Length of Crest when Francis Formula Discharge and Velocity is considered calculator uses Length of Weir Crest = (Francis Discharge/(1.84*(Still Water Head^(3/2)-Velocity Head^(3/2))))+(0.1*Number of End Contraction*Still Water Head) to calculate the Length of Weir Crest, The Length of crest when Francis formula discharge and velocity is considered is given as it applies to the area of reclamation can be defined as ' The distance, measured along the axis. Length of Weir Crest is denoted by Lw symbol.

How to calculate Length of Crest when Francis Formula Discharge and Velocity is considered using this online calculator? To use this online calculator for Length of Crest when Francis Formula Discharge and Velocity is considered, enter Francis Discharge (QFr), Still Water Head (HStillwater), Velocity Head (HV) & Number of End Contraction (n) and hit the calculate button. Here is how the Length of Crest when Francis Formula Discharge and Velocity is considered calculation can be explained with given input values -> 3.25325 = (8/(1.84*(6.6^(3/2)-4.6^(3/2))))+(0.1*4*6.6).

FAQ

What is Length of Crest when Francis Formula Discharge and Velocity is considered?
The Length of crest when Francis formula discharge and velocity is considered is given as it applies to the area of reclamation can be defined as ' The distance, measured along the axis and is represented as Lw = (QFr/(1.84*(HStillwater^(3/2)-HV^(3/2))))+(0.1*n*HStillwater) or Length of Weir Crest = (Francis Discharge/(1.84*(Still Water Head^(3/2)-Velocity Head^(3/2))))+(0.1*Number of End Contraction*Still Water Head). Francis Discharge is calculated from the empirical formula given by Francis, Still Water Head is the head of water which is still over weir, Velocity Head is represented in the term of length unit, also referred to as kinetic head represents the kinetic energy of the fluid & Number of End Contraction 1 can be described as the end contractions acting on a channel.
How to calculate Length of Crest when Francis Formula Discharge and Velocity is considered?
The Length of crest when Francis formula discharge and velocity is considered is given as it applies to the area of reclamation can be defined as ' The distance, measured along the axis is calculated using Length of Weir Crest = (Francis Discharge/(1.84*(Still Water Head^(3/2)-Velocity Head^(3/2))))+(0.1*Number of End Contraction*Still Water Head). To calculate Length of Crest when Francis Formula Discharge and Velocity is considered, you need Francis Discharge (QFr), Still Water Head (HStillwater), Velocity Head (HV) & Number of End Contraction (n). With our tool, you need to enter the respective value for Francis Discharge, Still Water Head, Velocity Head & Number of End Contraction 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 Francis Discharge, Still Water Head, Velocity Head & Number of End Contraction. We can use 3 other way(s) to calculate the same, which is/are as follows -
  • Length of Weir Crest = (Francis Discharge with Suppressed End*3)/(2*Coefficient of Discharge*sqrt(2*Acceleration due to Gravity)*((Height of Water above Crest of Weir+Velocity Head)^(3/2)-Velocity Head^(3/2)))
  • Length of Weir Crest = ((Francis Discharge*2)/(3*Coefficient of Discharge*sqrt(2*Acceleration due to Gravity)))^(2/3)+(0.1*Number of End Contraction*Height of Water above Crest of Weir)
  • Length of Weir Crest = ((3*Francis Discharge with Suppressed End)/(2*Coefficient of Discharge*sqrt(2*Acceleration due to Gravity)*(Still Water Head^(3/2)-Velocity Head^(3/2))))+(0.1*Number of End Contraction*Still Water Head)
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