# Sample Oral Exam Questions

Format: Each student will receive a first question randomly drawn from a stack of 3-by-5 cards. The student will have about 10-15 minutes to write the answer on the board. Once ready, the student will explain his/her answer to the professor, and the professor will ask follow-up questions. The student will then receive a second, smaller question on a different topic of the course, to be answered on the board in 5-10 minutes.

• Budgets and other preliminaries:

1. What is a control volume? Give three examples. Do a mass budget for one.
2. Establish the Bernoulli Principle. Specify the conditions under which it holds.
3. What is the Betz Limit? Sketch the approach of the theory.
4. Derive the 3D partial differential equation for conservation of mass.
5. Define circulation. What is its relation to vorticity?
6. What is the Bjerknes Circulation Theorem?
7. List a few dimensionless numbers used in EFM. What is the meaning of each?
• Processes:

1. What is a wave dispersion relation? Give an example.
2. Given the wave dispersion equation for gravity waves, discuss the limits of deep-water and shallow-water waves.
3. What is a seiche? What conditions have to be met for one to exist?
4. What are the ingredients of the Kelvin-Helmholtz instability? How does it proceed?
5. Define the Richardson number? What does it measure?
6. What is the vertical velocity scale for convection? Derive it.
7. What is buoyancy? How is it measured?
8. What is penetrative convection? Depict its evolution graphically? Give two examples.
9. What is the velocity profile of a turbulent flow along a rough boundary?
10. Using the velocity profile u(z) of a turbulent shear flow along a rough boundary, determine the drag coefficient if the fluid thickness is h.
11. Write the equations governing a turbulent jet.
12. Write the equations governing the rise of a plume in a uniform environment.
13. Given the equations governing a thermal in a stratified environment, derive the distance of its rise or fall.
• Atmosphere:

1. What is the adiabatic lapse rate? Discuss atmospheric stability based on it.
2. What is potential temperature? Why is this concept useful?
3. What is the ABL? Describe its typical daily cycle.
4. What is the Monin-Obukhov length? What is its use?
5. Describe the sea breeze.
6. Sketch the overall structure of the atmospheric general circulation on Earth. Identify its major components by giving their names.
7. Describe in broad lines what causes weather.
• Hydraulics:

1. Write down the budget equations for u and h.
2. What is uniform flow? Derive the Chezy formula.
3. Given the steady-state equation for h in the presence of friction, show the need to distinguish between mild and steep slopes.
4. What is hydraulic control? Give a couple of examples.
5. Describe the "lake discharge problem" and solve it in the case of a steep slope.
6. What is specific energy? Give its mathematical definition, sketch a graph of it, and describe its main features.
7. What is a hydraulic jump is? Write down the equations and solve them for the downstream flow variables in terms of the upstream flow variables.
8. Why don't we use a momentum budget for the flow over a bump but do for a hydraulic jump? Vice versa, why don't we use the Bernoulli Principle for a hydraulic jump but do for the flow over a bump?
9. Given the graph depicting sedimentation-erosion versus Reynolds number and Shields parameter (copy of graph provided), explain what is on the graph, give a physical interpretation for the Shields parameter, and relate the graph to the criterion u*^2 = 0.078 gd_s for erosion.