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

- Processes:
- What is a wave dispersion relation? Give an example.
- Given the wave dispersion equation for gravity waves, discuss the limits of deep-water and shallow-water waves.
- What is a seiche? What conditions have to be met for one to exist?
- What are the ingredients of the Kelvin-Helmholtz instability? How does it proceed?
- Define the Richardson number? What does it measure?
- What is the vertical velocity scale for convection? Derive it.
- What is buoyancy? How is it measured?
- What is penetrative convection? Depict its evolution graphically? Give two examples.
- What is the velocity profile of a turbulent flow along a rough boundary?
- 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*. - Write the equations governing a turbulent jet.
- Write the equations governing the rise of a plume in a uniform environment.
- Given the equations governing a thermal in a stratified environment, derive the distance of its rise or fall.

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

- Hydraulics:
- Write down the budget equations for
*u*and*h*. - What is uniform flow? Derive the Chezy formula.
- Given the steady-state equation for
*h*in the presence of friction, show the need to distinguish between mild and steep slopes. - What is hydraulic control? Give a couple of examples.
- Describe the "lake discharge problem" and solve it in the case of a steep slope.
- What is specific energy? Give its mathematical definition, sketch a graph of it, and describe its main features.
- 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.
- 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?
- 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.

- Write down the budget equations for