Questions and Answers of Fox And McDonald S Introduction To Fluid Mechanics

10.33 Demonstrate that the ducted propeller system shown in the figure has an efficiency ofwhen the forward speed is V1.For a specific design and operation, the ratios of velocity areDetermine the
10.32 This ducted propeller unit drives a ship through still water at a speed of 4 5m s. Within the duct the mean velocity of the water relative to the unit is 15 m s. Calculate the propulsive force
10.27 The absolute velocities and directions of the jets entering and leaving the blade system are as shown. Calculate the power transferred from the jet to the blade system and the blade angles
10.26 The velocity of the water jet driving this impulse turbine is 45 m s. The jet has a 75-mm diameter. After leaving the buckets the absolute velocity of the water is observed to be 15 m s in a
10.25 For a flow rate of 12 L s and turbine speed of 65 rpm, estimate the power transferred from the jet to the turbine wheel 3 m 50 mm Pipe Water 1.2 md. P10.25
10.22 Experimental test data for an aircraft engine fuel pump are presented below. This gear pump is required to supply jet fuel at 450 pounds per hour and 150 psig to the engine fuel controller.
10.21 Performance characteristics of a Howden Buffalo axial flow fan are presented below. The fan is used to power a wind tunnel with 1-ft-square test section. The tunnel consists of a smooth inlet
10.20 Performance data for a centrifugal fan of 3-ft diameter tested at 750 rpm arePlot the performance data versus volume flow rate. Calculate static efficiency, and show the curve on the plot. Find
10.19 A blower has a rotor with 12-in. outside diameter and 10-in.inside diameter with 1.5-in high rotor blades. The flow rate through the blower is 500 ft3 min at a rotor speed of 1800 rpm. The air
10.17 Performance data for a pump areEstimate the delivery when the pump is used to move water between two open reservoirs through 1200 ft of 12-in.-diameter commercial steel pipe containing two 90
10.12 A pump (Peerless 8AE20G, Appendix C) with the 20-in impeller operates at 1775 rpm at maximum efficiency. It supplies the pipe-line shown in the figure. Determine the pipeline loss coefficient K
10.11 Using the performance curves in Appendix C, select the smallest diameter Peerless 8AE20G pump operating at 1770 rpm that will deliver a flow of at least 2000 gpm for the pipeline shown.
10.9 Data measured during tests of a centrifugal pump driven at 3000 rpm areThe flow rate is 65 gpm and the torque applied to the pump shaft is 4.75 lbf ft. The pump efficiency is 75 percent, and the
10.8 Data from tests of a water suction pump operated at 2000 rpm with a 12-in.-diameter impeller arePlot the performance curves for this pump; include a curve of efficiency versus volume flow rate.
10.7 A centrifugal water pump designed to operate at 1200 rpm has dimensionsDetermine the flow rate at which the entering velocity has no tangential component. Draw the outlet velocity diagram, and
10.6 The absolute velocity of the water decreases from 41.5 m/s to 22:5 m/s as it passes through this blade system shown in the figure.The flow rate is 57 L/s. Determine the blade velocity U, the
10.5 Determine the force exerted by the jet on the single blade of a series of blades. Determine the power produced by the blade. 50 mm d water jet 45 m/s- 30 m/s P10.5
10.4 Dimensions of a centrifugal pump impeller areThe pump is driven at 1250 rpm while pumping water. Calculate the theoretical head and mechanical power input if the flow rate is 1500 gpm. Parameter
Consider two-dimensional laminar boundary-layer flow along a flat plate. Assume the velocity profile in the boundary layer is sinusoidal,Find expressions for:(a) The rate of growth of δ as a
9.26 The pressure difference as a function of angle for air flow around a circular cylinder at a Reynolds number of 80,000 is shown in the figure. Numerically integrate the pressure force and
9.21 A rotary mixer is constructed from two circular disks as shown.The mixer is rotated at 60 rpm in a large vessel containing a brine solution SG=1 1 . Neglect the drag on the rods and the motion
9.6 Plot the Blasius solution for the laminar boundary-layer velocity profile on a flat plate, with as the abscissa.Plot the approximate parabolic velocity profileon the same plot and compare the
9.5 Air flows in the entrance region of a square duct, as shown.The velocity is uniform, U0 =100 ft s, and the duct is 3 in. square.At a section 1 ft downstream from the entrance, the displacement
9.4 A fluid, with density ρ=1 5 slug ft3, flows at U =10 ft s over a flat plate 10 ft long and 3 ft wide. At the trailing edge, the boundarylayer thickness is δ=1 in. Assume that the velocity
9.1 A model of a river towboat is to be tested at 1:18 scale. The boat is designed to travel at 3.5 m/s in fresh water at 10 C. Estimate the distance from the bow where transition from a laminar to a
A simple and accurate viscometer can be made from a length of capillary tubing. If the flow rate and pressure drop are measured, and the tube geometry is known, the viscosity of a Newtonian liquid
8.50 An air conditioning system delivers 850 cfm of air at 55 F to two zones as shown in the figure below. The ducts are galvanized steel sheet metal. There are diffusers at the end of the ducts with
8.49 A swimming pool has a partial-flow filtration system. Water at 75 F is pumped from the pool through the system shown. The pump delivers 30 gpm. The pipe is nominal 3/4-in. PVC ID =0 824 in .The
8.47 Cooling water is pumped from a reservoir to rock drills on a construction job using the pipe system shown. The flow rate must be 600 gpm and water must leave the spray nozzle at 120 ft s.
8.44 In the system shown in the figure, the water velocity in the 12 in. diameter pipe is 8 ft/s. Determine the gage reading Elevation 170 ft! Elevation 200 ft 8 ft, 6-in.-diameter, 150 ft,
8.35 A 5-cm-diameter potable water line is to be run through a maintenance room in a commercial building. Three possible layouts for the galvanized iron water line are proposed as shown in the
8.33 Water flows from a larger pipe, diameter D1 =100 mm, into a smaller one, diameterD2 =50 mm, by way of a reentrant device. Find the head loss between points 1 and 2 . D Q=0.01 m/s P8.33
8.21 The following table gives data for the mean velocity in fully developed turbulent pipe flow at Re = 50,000 [5]:Fit the “power-law” profile for turbulent flow, Eq. 8.22, to the data and
8.18 Consider fully developed laminar flow in the annulus between two concentric pipes. The outer pipe is stationary, and the inner pipe moves in the x direction with speed V. Assume that the axial
8.11 A continuous belt, passing upward through a chemical bath at speed U0, picks up a liquid film of thickness h, density ρ, and viscosityμ. Gravity tends to make the liquid drain down, but the
8.9 An incompressible viscous liquid flows steadily down an incline due to gravity. The flow is laminar and the velocity profile derived in Example 5.9, iswhere θ is the slope of the incline and h
8.4 A hydraulic jack supports a load of 9000 kg. The following data are given:Estimate the rate of leakage of hydraulic fluid past the piston, assuming the fluid is SAE 30 oil at 30 C. Diameter of
The following wind tunnel test data from a 1:16 scale model of a bus are available:Using the properties of standard air, calculate and plot the dimensionless aerodynamic drag coefficient,versus
9.37 A baseball pitcher throws a ball 60 ft from the pitcher’s mound over home plate at 80 mph. A baseball has a mass of 5 oz and a circumference of 9 in. Determine the spin that should be placed
9.36 Rotating cylinders have been proposed as a means of ship propulsion as early as 1924. An original design used two rotors, each 10 ft in diameter and 50 ft high, rotating at up to 800 rpm.
9.35 A light airplane has 35-ft effective wingspan and 5.5-ft chord.It was originally designed to use a conventional (NACA 23015)airfoil section. With this airfoil, its cruising speed on a standard
9.34 The F-16 fighter aircraft weighs 26,000 lbf fully loaded, has a wing planform area of 300 ft2, and a maximum lift coefficient of 1.6. The limit on acceleration during turns in level flight is 5
9.33 An airplane with an effective lift area of 25 m2 is fitted with airfoils of NACA 23012 section (Fig. 9.23). The maximum flap setting that can be used at takeoff corresponds to configuration in
9.32A model airfoil of chord 6 in. and span 30 in. is placed in a wind tunnel with an air flow of 100 ft s at 70 F. It is mounted on a cylindrical support rod 1 in. in diameter and 10 in. tall.
9.31 A human-powered aircraft has a gross weight of 240 lbf including the pilot. Its wing has a lift coefficient of 1.5 and a lift-to-drag ratio of 70. Estimate the wing area needed and the pilot
9.30 The mean velocity over the top of a wing with a 1.8 m chord moving through air at 33.5 m/s is 40 m/s, and that over the bottom of the wing is 31 m/s. Determine the lift per meter of span and the
9.29 A model of wing has a 5 in. chord and 2.5 ft span and is tested at an angle of attack in a wind tunnel at 60 mph with air at 14.5 psia and 70oF. The lift and drag are measured at 6.0 lbf and 0.4
9.28 The lift and drag coefficients for a rectangular wing with a 10 m chord at takeoff are 1.0 and 0.05, respectively. Determine the span needed to lift 3560 kN at a take-off speed of 282
9.27 A rectangular airfoil of 40 ft span and 6 ft chord has lift and drag coefficients of 0.5 and 0.04, respectively, at an angle of attack of 6 . Determine the lift, drag, and horsepower needed to
9.25 A tractor-trailer rig has frontal area A=102 ft2 and drag coefficient CD =0 9. Rolling resistance is 6 lbf per 1000 lbf of vehicle weight. The specific fuel consumption of the diesel engine is
9.24 A fighter airplane is slowed after landing by dual parachutes deployed from the rear. Each parachute is 12 ft in diameter. The plane weighs 32,000 lbf and lands at 160 knots. Estimate the time
9.23 A typical fully-loaded highway transport truck has a weight of 350 kN, a frontal area of 11.5 m2, and a drag coefficient of 0.8. Using drag reduction devices such as a cab top deflector, chassis
9.22 A projectile reduces its speed from 250 m/s to 210 m/s over a horizontal distance of 150 m. The diameter and mass of the projectile are 11 mm and 16 g, respectively. Determine the average drag
9.20 A 0.3 m diameter circular disk is placed normal to a flow stream that has a speed of 5 m/s. Calculate the force and power if the fluid is (a) air and (b) water. If the disk is replaced with a
9.19 A 0.5-m-diameter hollow plastic sphere containing pollution test equipment is being dragged through the Hudson River in New York by a diver riding an underwater jet device. The sphere with an
9.18 A water tower consists of a 12-m-diameter sphere on top of a vertical tower 30 m tall and 2 m in diameter. Estimate the bending moment exerted on the base of the tower due to the aerodynamic
9.17 Atmospheric air is drawn into a low-speed wind tunnel where a 30 cm diameter sphere is mounted on a force balance to measure drag. The oil-filled manometer used to measure the static pressure
9.16 Small oil droplets with a specific gravity of 85 rise in a 30 C water bath. Determine the terminal speed of a droplet as a function of droplet diameter assuming the drag coefficient is given by
9.15 A steel sphere of 0.25 in. diameter has a velocity of 200 ft s at an altitude of 30,000 ft in the U.S. Standard Atmosphere. Calculate the drag force on this sphere.
9.14 The pilings for a bridge across a river that is 6 ft deep and flows at a maximum speed of 6 mph are made of wood poles 8 in. in diameter buried in the river bed. Estimate the bending moment at
9.13 A nuclear submarine cruises fully submerged at 27 knots. The hull can be approximated as a circular cylinder with a diameter of 11 m and length of 107 m. Estimate the percentage of the hull
9.12 A towboat for river barges is tested in a towing tank. The towboat model is built at a scale ratio of 1:13.5. Dimensions of the model are overall length 3.5 m, beam 1 m, and draft 0.2 m. The
9.11 Boundary-layer separation occurs when the shear stress at the surface becomes zero. Assume that a polynomial representation for the laminar boundary layer of the form, u U =a+bλ +cλ2 +dλ3,
9.10 Air at standard conditions and 20 m/s flows over one side of a horizontal smooth flat plate that is 1:5 m long and 0:8 m wide. A trip wire is used at the leading edge to ensure that the boundary
9.9 Water at a speed of 0.8 m/s and 10 C flows over a flat plate that is 0.35 m long and 1 m wide. The boundary layer on each side of the plate is laminar. Assume that the velocity profile may be
9.8 Air at 5 m/s, atmospheric pressure, and 20 C flows over both sides of a flat plate that is 0.8 m long and 0.3 m wide. Determine the total drag force on the plate. Determine the total drag force
9.7 For the flow of air over a flat plate, plot on the same graph the laminar boundary-layer thickness as a function of distance along the plate, up to the point of transition, for freestream speeds
An air flow rate of up to 1 m3/s at standard conditions is expected in a 0.25-m diameter duct. An orifice meter is used to measure the rate of flow. The manometer available to make the measurement
In the section of a cast-iron water pipe network shown in Fig. 8.17, the static pressure head (gage) available at point 1 is 100 ft of water, and point 5 is a drain (atmospheric pressure). Find the
Water rights granted to each citizen by the Emperor of Rome gave permission to attach to the public water main a calibrated, circular, tubular bronze nozzle [17]. Some citizens were clever enough to
Hamilton [22] reports results of measurements made to determine entrance losses for flow from a reservoir to a pipe with various degrees of entrance rounding. A copper pipe 10 ft long, with 1.5 in.
Spray heads in an agricultural spraying system are to be supplied with water through 500 ft of drawn aluminum tubing from an engine-driven pump. In its most efficient operating range, the pump output
A fire protection system is supplied from a water tower and standpipe 80 ft tall. The longest pipe in the system is 600 ft and is made of cast iron about 20 years old. The pipe contains one gate
Crude oil flows through a level section of the Alaskan pipeline at a rate of 1.6 million barrels per day 1 barrel =42 gal . The pipe inside diameter is 48 in.; its roughness is equivalent to
A 100-m length of smooth horizontal pipe is attached to a large reservoir. A pump is attached to the end of the pipe to pump water into the reservoir at a volume flow rate of 0 01 m3 s. What pressure
Aviscous, incompressible, Newtonian liquid flows in steady, laminar flow down a vertical wall. The thickness, δ, of the liquid film is constant. Since the liquid free surface is exposed to
A crankshaft journal bearing in an automobile engine is lubricated by SAE 30 oil at 210 F. The bearing diameter is 3 in., the diametral clearance is 0.0025 in., and the shaft rotates at 3600 rpm; it
A hydraulic system operates at a gage pressure of 20 MPa and 55 C. The hydraulic fluid is SAE 10W oil. A control valve consists of a piston 25 mm in diameter, fitted to a cylinder with a mean radial
• Explain the kinetic energy coefficient and its use.
• Describe the effects of Reynolds number on the fully developed velocity profile for turbulent pipe flow.
• Describe the differences between the laminar and turbulent shear stress distributions.
• Describe how laminar and turbulent flows affect the flow in the entrance region
10.36 A compressor has been designed for entrance conditions of 14.7 psia and 70 F with a rotating speed of 3200 rpm. The mass flow rate is 125 lbm/s. The compressor is tested on a day when the
10.35 An air compressor with a compression ratio of 7 is designed to take 8.9 kg/s air at 1 atmosphere and 20 C. The design point speed, power requirement, and efficiency are 600 rpm, 5.6 MW, and 80
10.34 Determine the maximum power that a wind turbine with a diameter of 130 m can produce in a winds of 35 km/hr and 70 km/hr. If the wind blows at 35 km/hr for 1500 hours and 70 km/hr for 500 hours
10.31 An airplane flies at 200 km h through still air of specific weight 12 N m3. The propeller is 2.4min diameter and its slipstream has a velocity of 290 km h relative to the fuselage. Calculate
10.30 A typical American multiblade farm windmill has D=7 ft and is designed to produce maximum power in winds with V =15 mph. Estimate the rate of water delivery as a function of the height to which
10.29 The propeller for the Gossamer Condor human-powered aircraft has D=12 ft and rotates at N =107 rpm. The wing loading is 0 4 lbf ft2 of wing area, the drag is approximately 6 lbf at 12 mph, the
10.28 A fanboat in the Florida Everglades is powered by a propeller with D=1 5 m driven at maximum speed, N =1800 rpm, by a 125 kW engine. Estimate the maximum thrust produced by the propeller at (a)
10.24 The runners on the Francis turbines installed at the Grand Coulee Dam on the Columbia River have diameters of 32.6 ft in diameter. At the rated conditions, each turbine develops 820,000 hp at
10.23 Conditions at the inlet to the nozzle of a Pelton wheel are p=700 psig and V =15 mph. The jet diameter is d =7 5 in and the nozzle loss coefficient is Knozle =0 04. The wheel diameter is D=8
10.18 Afire nozzle is supplied through 300 ft of 3-in.-diameter canvas hose with e=0 001 ft. Water from a hydrant is supplied at 50 psig to a booster pump on board the pumper truck. At design
10.16 Part of the water supply for the South Rim of Grand Canyon National Park is taken from the Colorado River [54]. A flow rate of 600 gpm taken from the river at elevation 3734 ft is pumped to a
10.15 A centrifugal pump operating at N =2265 rpm lifts water between two reservoirs connected by 300 ft of 6-in.-diameter and 100 ft of 3-in.-diameter cast-iron pipe in series. The gravity lift is
10.14 A four-stage boiler feed pump has suction and discharge lines of 10 cm and 7.5 cm inside diameter. At 3500 rpm, the pump is rated at 0 025 m3 s against a head of 125mwhile handling water at 115
10.10 At its best efficiency point η=0 87 , a mixed-flow pump, with D=16 in , delivers Q=2500 cfm of water at H =140 ft when operating at N =1350 rpm. Calculate the specific speed of this
10.3 For the centrifugal pump impeller described in Example 10.1, draw the outlet velocity diagram for a blade angle of 60 . Determine the ideal head rise and mechanical power input and compare to
10.2 The relevant variables for a turbomachine are, D, ω, Q, h, T, and ρ. Find the resulting Π-groups when D, ω, and ρ are the repeating variables. Discuss the meaning of each Π obtained.
10.1 The geometry of a centrifugal water pump is r1 =10 cm, r2 =20 cm, b1 =b2 =4 cm, β1 =30 , β2 =15 , and it runs at speed 1600 rpm. Estimate the discharge required for axial entry, the power
A smooth tennis ball, with 57 g mass and 64 mm diameter, is hit at 25 m s with topspin of 7500 rpm. Calculate the aerodynamic lift acting on the ball. Evaluate the radius of curvature of its path at

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