CIV E 632-COMPUTATIONAL HYDRAULICS AND HYDROLOGY
SPRING 2009
FINAL EXAM
MONDAY, MAY 18, 2009, 1900-2100

Name: ______________________ S.S. No. ________________ Grade: _______

Instructions: Closed book, closed notes. Use engineering paper. When you are finished, staple your work in sequence, and return this sheet with your work. Answer 10 questions.

  1. Explain the method of cascade of linear reservoirs. When is it used?

  2. What two kinds of errors arise in numerical modeling? Explain which one is related to stability, and which one to convergence. Why is numerical modeling a compromise between stability and convergence?

  3. Why is a second-order numerical scheme not necessarily better than a first-order scheme? What artifice is usually resorted to in order to provide stability at the expense of convergence?

  4. Why does the Muskingum-Cunge method work best at Courant number equal to 1? What happens for Courant greater than 1? For Courant less than 1?

  5. What is topology in the context of watershed/basin modeling?

  6. Do sedimentation bed transients (channel bottom perturbations) in alluvial rivers travel upstream or downstream? Explain.

  7. Why do dam-breach flood wave peaks eventually reach the same value at a certain distance downstream?

  8. Why is it better to use an explicit scheme rather than an implicit scheme in two-dimensional groundwater modeling? Explain.

  9. What is the cell Reynolds number in groundwater modeling? What does it affect?

  10. Should two-dimensional flow to a side river embayment convect (go straight into) or circulate (turn around)? Explain.

  11. How does the solution for the differential equation for DO sag curve differ from the classical Streeter-Phelps solution?