Strategy for Open Channel Flow

 

In a Nut Shell:  There are three types of open channel flow to address as shown in the table

below.  One should use the given information to identify the type and then apply the appropriate equations for the type.  These types include:

 

     Type      Description                                           Governing Equations

 

    1

 

Uniform (equilibrium) Flow 

 

Apply Manning's Equation  Q = (k/n) A RH2/3 So1/2 

 

 

  

    2

 

 

Gradually Varying flow

 

Apply Conservation of Mass and Conservation of Energy.

Plot Specific Energy Diagram as needed.

 

 

  

    3

 

 

Hydraulic Jump

 

 

Apply Conservation of Mass, Conservation of Linear

Momentum, and Conservation of Energy.

Plot Specific Energy Diagram as needed.

 

 

 

 

 

Type 1 equilibrium (or uniform) flow applications    Apply Manning's Equation.

 

                                     Given Data                                               Solve for:    

 

Q, L, ν, size, shape, roughness coefficient

    

      So

 

So, L, ν, size, shape, roughness coefficient

    

 V, y, Q

 

So, Q, L, ν, size, shape, roughness coefficient

   

   RH, y

 

Solve first two by direct calculation.  Last one requires iteration.  (Hardest type)

 

 

Click here to continue with strategies.

 

 

 


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