16-Civ-A5 Hydraulic Engineering, December 2019: worked solutions

Paper: National Exams — 16-Civ-A5 Hydraulic Engineering — December 2019 · 3 hours · closed book (one aid sheet) · six questions, complete any five (all six solved here) · each question 20 marks, equal-value parts.

Reference texts: Chin, Water-Resources Engineering (Pearson); Chow, Open-Channel Hydraulics (McGraw-Hill); Chaudhry, Open-Channel Flow (Springer); Wylie & Streeter, Fluid Transients in Systems (Prentice-Hall); Munson, Young & Okiishi, Fundamentals of Fluid Mechanics (Wiley); Roberson, Cassidy & Chaudhry, Hydraulic Engineering.

Governing relations supplied on the exam cover sheet. Hazen–Williams $Q = 0.278\,C\,D^{2.63}\,S^{0.54}$ with slope $S=\Delta h/L$ (SI, $Q$ in m³/s, $D$ in m); Manning $Q=\tfrac{1}{n}A\,R^{2/3}\,S^{1/2}$; Darcy–Weisbach $\Delta h = 0.0826\,\tfrac{fL}{D^5}Q^2$. Unless stated, local losses and velocity head are neglected, diameters are nominal, and water has $\rho=1000\ \text{kg/m}^3$, $\nu=1.31\times10^{-6}\ \text{m}^2/\text{s}$.

Note on question/figure labels. The transient plots on pages 2–3 are printed as “Figure Q4–A / Q4–B” but belong to Question 1 (the 450 mm and 750 mm pipe responses); “Figure 1” (valve main) is the figure for Question 3 and “Figure 2” (pipe grid) is for Question 4. Labels are given as printed; the figures are matched to their questions by content.

16-Civ-A5 Hydraulic Engineering: December 2019