Question

1. Why is there a separate formula for computing the critical depths for rectangular and non- rectangular cross sections? What is so different about each that it requires different formulas?

2. Explain the significance of the kinetic energy factor (alpha) used in the expression for total energy? Why is it usually ignored?

3. Explain why there are two unique depths for each specific energy value? Is there a point on the specific energy diagram in which there is only one depth associate with a specific energy value?

4. What is the difference between a measurement and regulation structure? Site an example(s) highlighting the difference between each.

5.  Why must we use the Strictler equation to compute Manning's "n" for rip-rap? Couldn't we just look up "n" values like we do for other surfaces? What's different about rip-rap?

Answer 1

1. Crirtical low to shich The flow Corregonding is Called as um4 Specific Energy is mini Critical flous we know that, E yr 2g Ca-Av) E ErnindE dy 0 dATdy dA Condition for cnitical flow 2 A We will be From the above equation, deniving different formulae for Gitical dipth for different shapes

£0 Rectangularfow ca T 2 b. 2 Parabelic channel A3TY T T 2. T the differerd shapes have differurd areas, topioidths critial depth fomulae changes. .: Hence