MAE335 Midterm Exam (2 hours, 4 questions) October 15, 2013

Closed book. Only the provided equation sheet may be used.

No Computers, phones, tablets, and etc. allowed. Usage will result in a 0.

Scientific and graphing calculators are allowed; show all work!

Any cheating that is discovered in class or during the grading will result in a 0.

1. (20%) Answer the following questions in your exam booklet: TRUE or FALSE

a. Shear stress is 0 at the wall since velocity is 0.

b. Bernoulli’s equation is not always limited to flows along the same streamline.

c. Resultant horizontal force on any wall can be calculated using the wall’s vertical projection.

d. Buoyancy of a hollow object is different from that of a filled object with the same external

dimensions.

2. (30%) An observation deck at Pier 39 in San Francisco is shown below. Determine the

amplitude of the resultant force that the water exerts on to the deck along ABC. Width of the

deck is 5m.

3. (30%) Consider uniform flow past an airfoil. It

leaves a parabolic-shaped wake behind as shown in

the figure on the right. Assume pressure outside the

streamline to be constant.

a. If w is the width of the airfoil, express the

force Rx on the airfoil due to the flow.

b. Calculate the drag coefficient, CD, of the

airfoil, given that CD=F/(ρv2Lw)

4. (20%) Consider a steady, 2-D, inviscid, incompressible flow with a velocity field ,

.

a. Does the flow satisfy conservation of mass?

b. Find the pressure field p(x,y) if p(0,0) = pa.

2h

2l

v v

① ②

L

L

streamline

0.25v

1m

5m

4m

A B

C