MEE 311 Final, Fall 2007

Lebanese American University Byblos Campus School of Engineering and Architecture Department of Civil Engineering FLUID MECHANICS _CIE 320 Final Exam January 31,2008 1 indicate the proper units, ude all necessary explanations, > stions that add up to 100% (i.e, DROP ANY TWO ESTIOWNS of 13% each), > ‘ok and notes, » Assume any missing information that is necessary, > Questions have weights as indicated. » Exam consists of 21 pages. Do not unstaple the exam. Question 1 (10 %) Water flows down the ramp shown in the channel. The channel width decreases from 15 ft at section (1) to 9 ft at section (2). For the conditions shown, determine the flow rate. Width = 15 ft Neale chrg fhe losses hus te conbra ctw Question 2 (12 %) Water flows over a spillway at 5000cfs. For dynamic similarity, what should be the model scale if the flow rate over the model is to be 45 cfs? The force exerted on a certain area of the model is measured to be 1.0 lb, what would be the force on the corresponding area of the prototype? = 9.09423 # Question 3 (13 %) ee ioes What size of asphalted cast iron pipe (k = 0.005075 in) is needed to carry a water discharge of 12 cfs and with a head loss of 4 ft per 1000 ft of pipe? Mate : ~LG al > Boy v Tey © popautastes's yu 4 —, 2 i 0.000 ty edt = ott nto” AF sss ae I} 4. => + = Qeoco2S a} V= Se oo 0. ¥E¢10" => ce 0.01 SS es =.9 Ae Question 4 (13 %) Determine the magnitude of the hori- zontal component of the anchoring force required to hold in place the sluice gate shown. Compare this result with the size of the horizontal component of the anchoring force required to hold in place the sluice gate when it is closed and the depth of water upstream is 10 ft. Question 5 (13 %) Water is supplied at 150 ft/s and 60 psi py = 60 psi to a hydraulic turbine through a 3-ft-inside — g.st.cn 4) 2 = 15 an diameter inlet pipe as indicated. The ae turbine discharge pipe has a 4-ft-inside diameter. The static pressure at section (2), 10 ft below the turbine inlet, is 10 in. Hg vacuum. If the turbine develops 2500 hp, determine the rate of loss of available energy between sections (1) and (2). O-. ISo H ys Ni ~ eer", Question 6 (13 %) Water flows steadily down the inclined pipe as indicated. Determine the following: 1. The difference in pressure P; — P2 2. The headloss between the two sections. 11 Question 7 (13 %) 1. Determine the flow rate through the Venturi meter shown if ideal conditions exist. For what flow rate through the Venturi will cavitation begin if P; = 275 KPa gage, atmospheric pressure is 101 KPa, and the vapor pressure is 5.2 kPa (abs)? @ - wT @.031) ¢ ¥.| 14 Question 8 (13 %) What horsepower must be supplied to the water to pump 2.5 cfs at 68°F from the lower to the upper reservoir? Assume that the head loss in the pipes is given by hy = 0.015 (L/D)(V?/2g), where L is the length of the pipe in feet, D is the pipe diameter in ft. SKETCH E.L. and H.G.L. EE OD &@ o+ D+ 0+ hp = or Nor OF hi, + hua w x BS Hes : . iG see \, y. TQ 4 aN pe 3 4 Rede Hye gion = 140 ft Elevation = 9 15