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

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
Jet engines burn fuel at a rate proportional to thrust delivered. The optimum cruise condition for a jet aircraft is at maximum speed for a given thrust. In steady level flight, thrust and drag are
A dragster weighing 1600 lbf attains a speed of 270 mph in the quarter mile. Immediately after passing through the timing lights, the driver opens the drag chute of area A=25ft2. Air and rolling
A cylindrical chimney 1 m in diameter and 25 m tall is exposed to a uniform 50 km hr wind at standard atmospheric conditions.End effects and gusts may be neglected. Estimate the bending moment at the
A supertanker is 360 m long and has a beam width of 70 m and a draft of 25 m. Estimate the force and power required to overcome skin friction drag at a cruising speed of 13 kt in seawater at 10 C.
Water flows at U =1m s past a flat plate with L=1 min the flow direction. The boundary layer is tripped so it becomes turbulent at the leading edge. Evaluate the disturbance thickness, δ,
Use the numerical results presented in Table 9.1 to evaluate the following quantities for laminar boundary-layer flow on a flat plate:(a) δ δ (for η =5 and as η ∞).(b) υ U at the
A laboratory wind tunnel has a test section that is 305 mm square. Boundary-layer velocity profiles are measured at two crosssections and displacement thicknesses are evaluated from the measured
Explain the effects of pressure gradients on a boundary layer.
Describe a boundary layer and the parameters that characterize it.
The end effector of the gantry robot of Prob. 10.26 is working against a force loading of 20ˆi1+10tˆj1 N and a constant torque loading of 5ˆj1 N · m as it follows the trajectory described in
The end effector of the SCARA robot of Prob. 10.24 is working against a force loading of 10ˆi1 +5tkˆ 1 lb and a constant torque loading of 25kˆ 1 in ·lb as it follows the trajectory described in
The gantry robot of Prob. 10.26 is to travel a path for which the origin of the end effector O5 follows the straight line given by RO5 (t) = (120t +300)ˆi1 −150ˆj1+(90t +225)kˆ 1 mm, with t
The SCARA robot of Prob. 10.24 is to be guided along a path for which the origin of the end effector O5 follows the straight line given by RO5 (t) = (1.6t +4.0)ˆi1 +(1.2t +3.0)ˆj1 +2.0kˆ 1 in,
For the gantry robot of Prob. 10.26 in the posture described, find the instantaneous velocity and acceleration of the same tool point, x5 = y5 =0, z5 = 45 mm, if the actuators have
For the SCARA robot of Prob. 10.24 in the posture described, find the instantaneous velocity Figure P10.26 a12 = a23 = a34 = a45 = 0, α12 = 90◦,α23 = −90◦, α34 = α45 = 0, θ12 = θ23 =
Repeat Prob. 10.26 using arbitrary (symbolic)values for the joint variables.
For the gantry robot shown, find the transformation matrix T15 relating the posture of the tool coordinate system to the ground coordinate system when the joint actuators are set to the values φ1
For the SCARA robot, find the transformation matrix, T15, relating the posture of the tool coordinate system to the ground coordinate system when the joint actuators are set to the values φ1 =
The figure shows the top, front, and profile views of an RSRC crank and oscillating-slider linkage. Link 4, the oscillating slider, is rigidly attached to a round rod that rotates and slides in the
The figure shows the top, front, and auxiliary views of a spatial slider-crank RSSP linkage. In the construction of many such linkages, a provision is made to vary the angle β; thus, the stroke of
Use vector algebra to make complete velocity and acceleration analyses of the linkage of Fig. P10.10 at the posture specified.
For the spheric RRRR linkage determine whether the crank is free to turn through a complete revolution.If so, find the angle of oscillation of link 4 and the advance-to-return ratio.Figure P10.10
Determine the advance-to-return ratio for Prob. 10.5.What is the total angle of oscillation of link 4?
For the spheric RRRR linkage in the posture shown, use vector algebra to make complete velocity and acceleration analyses at the posture indicated.Figure P10.5 RO2O = 7kˆ in, RO4O = 2ˆi in, RAO2
For the linkage of Fig. P10.1 with VA = −50ˆj mm/s, use vector analysis to find the angular velocities of links 2 and 3 and the velocity of point B at the posture specified
For the SSC linkage shown in Fig. P10.1, express the posture of each link in vector form.
Use the Kutzbach criterion to determine the mobility of the SSC linkage. Identify any idle freedoms and state how they can be removed. What is the nature of the path described by point B?Figure P10.1
Synthesize a dwell mechanism using the idea suggested in Fig. 9.42a and the Hrones and Nelson atlas.Rocker 6 is to have a total angular displacement of 60◦. Using this displacement as the abscissa,
Synthesize a four-bar linkage to obtain a coupler curve having an approximate straight-line segment.Then, using the suggestion included in Fig. 9.42b or Fig. 9.44b, synthesize a dwell motion. Using
The figure shows a coupler curve generated by a four-bar linkage (not shown). Link 5 is to be attached to the coupler point, and link 6 is to be a rotating member with O6 as the frame connection. In
Synthesize a linkage to move AB successively through postures 1, 2, and 3.
Synthesize a linkage to move AB from posture 1 to posture 2 and return.Figure P9.10
Design a spring-operated four-bar linkage to support a heavy lid, like the trunk lid of an automobile. The lid is to swing through an angle of 80◦ from the closed to the open posture. The springs
Two postures of a folding seat used in the aisles of buses to accommodate extra passengers are shown.Design a four-bar linkage to support the seat so that it will lock in the open posture and fold to
Design a crank and rocker for a six-bar linkage such that the slider in Fig. P9.6 reciprocates a distance of 800 mm with an advance-to-return ratio of 1.12;use a = r4 = 1 200 mm and r5 = 1 800 mm.
Design a crank and coupler to drive rocker 4 such that slider 6 reciprocates through a distance of 16 in with an advance-to-return ratio of 1.20. Use a = r4 =16 in and r5 = 24 in with r4 vertical at
A crank-rocker linkage is to have a rocker of 6 ft length and a rocking angle of 75◦. If the advance-to-return ratio is to be 1.32, what is a suitable set of link lengths for the remaining three
The rocker of a crank-rocker linkage is to have a length of 500 mm and swing through a total angle of 45◦ with an advance-to-return ratio of 1.25. Determine a suitable set of dimensions for r1, r2,

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