First Test Spring 2014 Hydraulic Engineering Key

Full Name ______(100/104)

Closed book, two pages of notes one side in your own handwriting.

You must show the work for all problems to get credit.

Casio: All fx-115 models.
Hewlett Packard: The HP 33s and HP 35s models, but no others.
Texas Instruments: All TI-30X and TI-36X models.

By my signature below, I hereby swear that I have neither received aid from any other student, nor have I given aid to any other student on this exam.Moreover, I swear that I have not committed any form of academic dishonesty and have maintained ethical integrity in accordance with the UTEP Handbook of Operating Procedures, the UTEP Civil Engineering Honor Code, and the ASCE Code of Ethics.

Signature: ______

By my signature below, I swear that I have not witnessed any other student commit any form of academic dishonesty with regard to this exam.

Signature: ______

1. (16) (8)Circle any portion (s) of the entire figure where the water pressure is zero (atmospheric); (4) label the point where pressure is lowest; (4) label the location in the entire figure where pressure is the greatest.

P=0 at left tank top, two places where HGL crosses center of pipe, at exit

Highest P at bottom of tank, lowest P at high point in pipe (or just beyond)

2. Figure should say “lift” type check valve, friction factor is 0.017, atmospheric pressure is 101.3 kPa, flow velocity is 4 ft/s (1.22 m/s) , the tank on the left is pressurized at greater than atmospheric pressure.

a) (12) what is the friction slope in the pipe (head loss per unit length)?
hl/L = V^2/2g f/D = 4^2/(2*32.2)*0.017/0.3333 = 0.0127, dimensionless

b) (4) Between points 2 and 3, the pressure (increases, decreases, stays the same ) because _____head loss can only come from pressure when Z and V are constant
c) (4) Going into the globe valve the HGL (declines, stays the same, increases) because ___energy loss must come from pressure when V and Z are constant
d) (4) at the water surface near “A” the HGL and EGL are: ( above the water surface, at the water surface, below the water surface) because __water is under pressure so HGL must be above water surface and EGL is always above HGL______

3. (12) The flow between two locations in an unconfined aquifer can be estimated using Darcy’s Law. If the hydraulic conductivity is 10-5 cm/s and the aquifer is thick relative to the change in head, calculate the specific discharge between the two wells in m^3/m^2/s.

V=-K (delta H/delta X) = 10^-7 m/s 3/780 = 9.9e-8 m/s

4. (20) The drainage basin has a area of 5800000 m^2 and the following hydrograph was measured. Create a unit (1 cm) hydrograph. Draw the hydrograph on the figure, show all your work or get no credit. The second copy of the graph is in case you make a mistake and want to start over. Draw the unit hydrograph on the graph.

5. Jonjuga took the FE exam in May of 2011 and failed. After spending the past three years working for Minywage Fast Food, she now wishes she had studied more in school. Now she’s trying again and here’s her problem. Her rich dad will reward you for helping her!

The watershed of interest is 13 hectares with a time of concentration of 30 minutes. The site is mostly fish ponds and vegetable gardens. Jonjuga and you are required to design for the 100 year storm.

a)(12) What is the 100 year peak discharge according to the rational method? (be sure to show all your work!).
Q=CIA = 0.45 0.2 m/hr * 13*10^4 m^2 = 3.25 m^3/s

b)(8) What is the probability her design (assumed to be correct) will fail next year?
1/100

c)(8) What is the probability her design will fail in the next 12 years?

P=1-(1-p)^12 = 1-0.99^12 = 0.114

6. (4) When interpreting experimental data it is important to recognize the accuracy and precision of the data. Likewise when fitting models it is important to be sure the model actually fits the data. Label each of the four figures below in terms of: (high precision, low precision), (high accuracy, low accuracy). Give two answers for each target.

Grading: half point for only one answer, round down