16.5.3. Energy Gradient Line and Energy Losses

Try these first

1. 1.

   Define specific energy in open channel flow.

   Hint

   Think about energy in terms of weight, fluid dynamics, and height.

2. 2.

   What does a Froude number less than 1 indicate?

   Hint

   Recall how flow behaves compared to wave speed.

3. 3.

   What is the formula for specific energy?

   • E = y + (v^2)/(2g)
   • E = y/(v^2)
   • E = (2g)/y

   Hint

   Recall the formula involving velocity and gravitational effects.

4. 4.

   True or False: A hydraulic jump occurs from subcritical to supercritical flow.

   • True
   • False

   Hint

   Think about the transition in terms of flow dynamics.

5. 5.

   If the flow depth is 3 m and the flow velocity is 5 m/s, calculate the specific energy and determine if it is subcritical, critical, or supercritical.

   Hint

   Look at the relationship between energy terms and the definition of the Froude number.

6. 6.

   Design an open channel flow for a bridge that needs to manage energy losses. Given that the bridge width is 10 m and flow depth is 4 m with a velocity of 8 m/s, calculate energy losses during a hydraulic jump, assuming flow past the bridge is supercritical.

   Hint

   You will use the concept of energy conservation during hydraulic jumps.