Concept explainers
A hydroponic garden uses the 10-m-long perforated-pipe system in Fig. D6. 1 to deliver water at 20°C. The pipe is 5 cm in diameter and contains a circular hole every 20 cm. A pump delivers water at 75 kPa (gage) at the entrance, while the other end of the pipe is closed, if you attempted, for example, Prob. P3.125, you know that the pressure near the closed end of a perforated “manifold” is surprisingly high, and there will be too much flow through the holes near that end. One remedy is to vary the hole size along the pipe axis. Make a design analysis, perhaps using a personal computer, to pick the optimum hole size distribution that will make the discharge flow rate as uniform as possible along the pipe axis. You are constrained to pick hole sizes that correspond only to commercial (numbered) metric drill-bit sizes available to the typical machine shop.
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Fluid Mechanics
- You wish to water your garden with 100 ft of 5/8-in-diameterhose whose roughness is 0.011 in. What will be the delivery,in ft3/s, if the gage pressure at the faucet is 60 lbf/in2?If there is no nozzle (just an open hose exit), what is thethe maximum horizontal distance the exit jet will carry?arrow_forwardWater at 20 ° C fl ows through a long elliptical duct 30 cmwide and 22 cm high. What average velocity, in m/s, wouldcause the weight fl ow to be 500 lbf/s?arrow_forwardFor the pipe-fl ow-reducing section of Fig. P3.54, D 1=8 cm, D 2 = 5 cm, and p 2 = 1 atm. All fl uids are at 20 ° C. IfV 1 = 5 m/s and the manometer reading is h =58 cm, estimatethe total force resisted by the fl ange bolts.arrow_forward
- Water at 20 ° C fl ows steadily through the tank in Fig.P3.101. Known conditions are D 1 = 8 cm, V 1 = 6 m/s, andD 2 = 4 cm. A rightward force F = 70 N is required to keepthe tank fi xed. ( a ) What is the velocity leaving section 2?( b ) If the tank cross section is 1.2 m 2 , how fast is the watersurface h ( t ) rising or falling?arrow_forwardThe boat in Fig. P3.88 is jet-propelled by a pump thatdevelops a volume flow rate Q and ejects water out thestern at velocity V j . If the boat drag force is F = kV 2 , wherek is a constant, develop a formula for the steady forwardspeed V of the boat.arrow_forwardThe bottom of a river has a 4-m-high bump that approximates a Rankine half-body, as in Fig. The pressure at point B on the bottom is 130 kPa, and the river velocity is 2.5 m/s. Use inviscid theory to estimate the water pressure at point A on the bump, which is 2 m above point B.arrow_forward
- An 8-in model pump delivering 180°F water at 800 gal/minand 2400 r/min begins to cavitate when the inlet pressureand velocity are 12 lbf/in2 absolute and 20 ft/s, respectively.Find the required NPSH of a prototype that is4 times larger and runs at 1000 r/min.arrow_forwardtall water tank discharges through a well-rounded orifi ce,as in Fig. P3.95. Use the Torricelli formula to estimate the exit velocity. ( a ) If, at this instant, the forceF required to hold the plate is 40 N, what is the depth h ?( b ) If the tank surface is dropping at the rate of 2.5 cm/s,what is the tank diameter D ?arrow_forwardSteam enters a horizontal turbine at 350 lbf/in 2 absolute,580 ° C, and 12 ft/s and is discharged at 110 ft/s and 25 ° Csaturated conditions. The mass fl ow is 2.5 lbm/s, and theheat losses are 7 Btu/lb of steam. If head losses are negligible,how much horsepower does the turbine develop?arrow_forward
- Incompressible steady fl ow in the inlet between parallelplates in Fig. P3.17 is uniform, u = U 0 = 8 cm/s, whiledownstream the fl ow develops into the parabolic laminar profile u = az ( z 0 - z ), where a is a constant. If z 0 = 4 cm and thefl uid is SAE 30 oil at 20 ° C, what is the value of u max in cm/s?arrow_forwardA cylindrical tank 1 m diameter and 3 meter high contains 1m of water, 1.2 m of oil (SG=0.8) and air under a pressure of 15 kPa. Find the theoretical velocity of the jet through a 5 cm diameter orifice 30 cm above the bottom of the tank.arrow_forwardIn Fig. P3.121 the fl owing fl uid is CO 2 at 20 ° C. Neglect losses.If p 1 = 170 kPa and the manometer fl uid is Meriam red oil(SG = 0.827), estimate ( a ) p 2 and ( b ) the gas fl ow rate in m 3 /h.arrow_forward
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