Fox and McDonald's Introduction to Fluid Mechanics
9th Edition
ISBN: 9781118912652
Author: Philip J. Pritchard, John W. Mitchell
Publisher: WILEY
expand_more
expand_more
format_list_bulleted
Textbook Question
Chapter 9, Problem 126P
How do cab-mounted wind deflectors for tractor-trailer trucks work? Explain using diagrams of the flow pattern around the truck and pressure distribution on the surface of the truck.
Expert Solution & Answer
Want to see the full answer?
Check out a sample textbook solutionStudents have asked these similar questions
A small three (3) blade turbine with 10 meter long blades is shut down due to wind speeds being
35 m/s. The turbine has a brake on the low speed shaft rotor to keep the rotor from spinning in
these circumstances. However, a maintenance man accidentally sets the blades to have an
angle of attack of 10 degrees against the incoming wind when the rotor is facing into the wind.
The blades have a constant chord of 0.5 meters, and have CI = 2TTA where a is measure in
radians. Assume also that the air density is 1.25 kg/m³. Approximately how much torque must
the brake restrain?
The spoiler, shown in figure 1, will be fitted at the back end of a stock car to give it downforce on the track. The pressure distribution and average shear stress on the top surface are given and the data on the bottom surface can be neglected. The car can reach a maximum speed of 270 km/h on the track. The spoiler has a length and a widthof 1.2 m and 0.3 m, respectively. The density of the air is 1.2 kg/m2. Calculate the lift and drag coefficients of the spoiler.
1) For a parallel laminar flow over flat plates, the friction coefficient depends only on the Reynolds number. In the fully rough turbulent regime, the friction coefficient only relates to the surface roughness. True or False
2) a car is placed in a large wind tunnel for a full scale test. The upstream velocity is determined to be 20 m/s. The frontal area of the car is 15 m2. If the force acting on the car in the flow direction is measured to be 1000 N, what is the drag coefficient of this car? Assume the air density = 1.14 kg/m3.
a)
0.15
b)
0.29
c)
0.34
d)
0.34 Ns/m
3) Drag force include friction drag and pressure drag. Friction drag increase with the increment of viscosity of the fluid. True or False
Chapter 9 Solutions
Fox and McDonald's Introduction to Fluid Mechanics
Ch. 9 - The roof of a minivan is approximated as a...Ch. 9 - A model of a river towboat is to be tested at 1:18...Ch. 9 - For flow over a smooth plate, what approximately...Ch. 9 - A model of a thin streamlined body is placed in a...Ch. 9 - A student is to design an experiment involving...Ch. 9 - A 1 m 2 m sheet of plywood is attached to the...Ch. 9 - The extent of the laminar boundary layer on the...Ch. 9 - Velocity profiles in laminar boundary layers often...Ch. 9 - An approximation for the velocity profile in a...Ch. 9 - Evaluate / for each of the laminar boundary-layer...
Ch. 9 - Evaluate the displacement thickness and the...Ch. 9 - Evaluate the displacement thickness and the...Ch. 9 - A fluid, with density = 1.5 slug/ft3, flows at U...Ch. 9 - Solve Problem 9.13 with the velocity profile at...Ch. 9 - Air flows in a horizontal cylindrical duct of...Ch. 9 - Evaluate the displacement thickness and the...Ch. 9 - Evaluate the displacement thickness and the...Ch. 9 - A laboratory wind tunnel has a test section 25 cm...Ch. 9 - Air flows in the entrance region of a square duct,...Ch. 9 - A flow of 68F air develops in a flat horizontal...Ch. 9 - A flow of air develops in a horizontal cylindrical...Ch. 9 - Using numerical results for the Blasius exact...Ch. 9 - Using numerical results obtained by Blasius (Table...Ch. 9 - Using numerical results obtained by Blasius (Table...Ch. 9 - A smooth flat plate 2.4 m long and 0.6 m wide is...Ch. 9 - Consider flow of air over a flat plate. On one...Ch. 9 - A thin flat plate, L = 9 in. long and b = 3 ft...Ch. 9 - For a laminar boundary layer on a flat plate,...Ch. 9 - Air at atmospheric pressure and 20C flows over...Ch. 9 - A thin flat plate is installed in a water tunnel...Ch. 9 - Assume laminar boundary-layer flow to estimate the...Ch. 9 - Assume laminar boundary-layer flow to estimate the...Ch. 9 - Assume laminar boundary-layer flow to estimate the...Ch. 9 - Prob. 34PCh. 9 - Water at 10C flows over a flat plate at a speed of...Ch. 9 - Use the momentum integral equation to derive...Ch. 9 - A smooth flat plate 1.6 ft long is immersed in 68F...Ch. 9 - Prob. 38PCh. 9 - A developing boundary layer of standard air on a...Ch. 9 - Assume the flow conditions given in Example 9.3....Ch. 9 - A flat-bottomed barge having a 150 ft 20 ft...Ch. 9 - European InterCity Express trains operate at...Ch. 9 - Grumman Corp. has proposed to build a magnetic...Ch. 9 - Repeat Problem 9.32, for an air flow at 80 ft/s,...Ch. 9 - The velocity profile in a turbulent boundary-layer...Ch. 9 - The U.S. Navy has built the Sea Shadow, which is a...Ch. 9 - The two rectangular smooth flat plates are to have...Ch. 9 - Standard air flows over a horizontal smooth flat...Ch. 9 - Air at standard conditions flows over a flat...Ch. 9 - A uniform flow of standard air at 60 m/s enters a...Ch. 9 - A laboratory wind tunnel has a flexible upper wall...Ch. 9 - Air flows in a cylindrical duct of diameter D = 6...Ch. 9 - Perform a cost-effectiveness analysis on a typical...Ch. 9 - Table 9.1 (on the web) shows the numerical results...Ch. 9 - A fluid flow enters the plane-wall diffuser that...Ch. 9 - For flow over a flat plate with zero pressure...Ch. 9 - A flat-bottomed barge, 80 ft long and 35 ft wide,...Ch. 9 - A towboat for river barges is tested in a towing...Ch. 9 - Plot the local friction coefficient cf, the...Ch. 9 - A smooth plate 3 m long and 0.9 m wide moves...Ch. 9 - Resistance of a barge is to be determined from...Ch. 9 - A nuclear submarine cruises fully submerged at 27...Ch. 9 - You are asked by your college crew to estimate the...Ch. 9 - The drag coefficient of a circular disk when...Ch. 9 - A steel sphere of 0.25 in. diameter has a velocity...Ch. 9 - A steel sphere (SG = 7.8) of 13 mm diameter falls...Ch. 9 - A sheet of plastic material 0.5 in. thick, with...Ch. 9 - As part of the 1976 bicentennial celebration, an...Ch. 9 - What constant speed will be attained by a lead (SG...Ch. 9 - Assuming a critical Reynolds number of 0.1,...Ch. 9 - Glass spheres of 0.1 in. diameter fall at constant...Ch. 9 - A rotary mixer is constructed from two circular...Ch. 9 - Calculate the drag of a smooth sphere of 0.3 m...Ch. 9 - Calculate the drag of a smooth sphere of 0.5 m...Ch. 9 - A cylindrical chimney 0.9 m in diameter and 22.5 m...Ch. 9 - The resistance to motion of a good bicycle on...Ch. 9 - Ballistic data obtained on a firing range show...Ch. 9 - A standard marine torpedo is 0.533 m in diameter...Ch. 9 - A large truck has an essentially boxlike body that...Ch. 9 - At a surprise party for a friend youve tied a...Ch. 9 - A 0.5-m-diameter hollow plastic sphere containing...Ch. 9 - A simple but effective anemometer to measure wind...Ch. 9 - The Willis Tower (formerly the Sears Tower) in...Ch. 9 - It is proposed to build a pyramidal building with...Ch. 9 - Calculate the drag forces on a 1/200 scale model...Ch. 9 - A circular disk is hung in an air stream from a...Ch. 9 - A vehicle is built to try for the land-speed...Ch. 9 - An F-4 aircraft is slowed after landing by dual...Ch. 9 - A tractor-trailer rig has frontal area A = 102 ft2...Ch. 9 - A 180hp sports car of frontal area 1.72 m2, with a...Ch. 9 - An object falls in air down a long vertical chute....Ch. 9 - Prob. 99PCh. 9 - A light plane tows an advertising banner over a...Ch. 9 - The antenna on a car is 10 mm in diameter and 1.8...Ch. 9 - Consider small oil droplets (SG = 0.85) rising in...Ch. 9 - Standard air is drawn into a low-speed wind...Ch. 9 - A small sphere with D = 6 mm is observed to fall...Ch. 9 - A tennis ball with a mass of 57 g and diameter of...Ch. 9 - A water tower consists of a 12-m-diameter sphere...Ch. 9 - A cast-iron 12-pounder cannonball rolls off the...Ch. 9 - A rectangular airfoil of 40 ft span and 6 ft chord...Ch. 9 - A rectangular airfoil of 9 m span and 1.8 m chord...Ch. 9 - Why is it possible to kick a football farther in a...Ch. 9 - If CL = 1.0 and CD = 0.05 for an airfoil, then...Ch. 9 - A wing model of 5 in. chord and 2.5 ft span is...Ch. 9 - A barge weighing 8820 kN that is 10 m wide, 30 m...Ch. 9 - A spherical sonar transducer with 15 in. diameter...Ch. 9 - While walking across campus one windy day, an...Ch. 9 - If the mean velocity adjacent to the top of a wing...Ch. 9 - The NACA 23015 airfoil is to move at 180 mph...Ch. 9 - A human-powered aircraft has a gross weight of 240...Ch. 9 - WiffleTM balls made from light plastic with...Ch. 9 - A model airfoil of chord 6 in. and span 30 in. is...Ch. 9 - An antique airplane carries 50 m of external guy...Ch. 9 - How do cab-mounted wind deflectors for...Ch. 9 - An airplane with an effective lift area of 25 m2...Ch. 9 - The U.S. Air Force F-16 fighter aircraft has wing...Ch. 9 - A light airplane, with mass M = 1000 kg, has a...Ch. 9 - A light airplane has 35-ft effective wingspan and...Ch. 9 - Assume the Boeing 727 aircraft has wings with NACA...Ch. 9 - Jim Halls Chaparral 2F sports-racing cars in the...Ch. 9 - Some cars come with a spoiler, a wing section...Ch. 9 - Roadside signs tend to oscillate in a twisting...Ch. 9 - Air moving over an automobile is accelerated to...Ch. 9 - A class demonstration showed that lift is present...Ch. 9 - Rotating cylinders were proposed as a means of...Ch. 9 - A baseball pitcher throws a ball at 80 mph. Home...
Additional Engineering Textbook Solutions
Find more solutions based on key concepts
The force for equilibrium in each cord.
Engineering Mechanics: Statics & Dynamics (14th Edition)
In Figure 31.17, a form-milling operation and cutters are shown. The gear is to be made from 4340 steel, Rc 50 ...
DeGarmo's Materials and Processes in Manufacturing
Repeat Problem 1.54 if the flow inside the apparatus is liquid water (=1000kg/m3) instead of air. Find the pres...
Fundamentals Of Thermodynamics
Also, find the angle .
Engineering Mechanics: Statics
ICA 7-32
In NCAA basketball, the center circle diameter which encompasses the free throw line is 3.66 meters [m...
Thinking Like an Engineer: An Active Learning Approach (4th Edition)
The following readings are obtained from each gage: a = 800(106), b = 520(106), c = 450(106). Determine the in-...
Mechanics of Materials (10th Edition)
Knowledge Booster
Learn more about
Need a deep-dive on the concept behind this application? Look no further. Learn more about this topic, mechanical-engineering and related others by exploring similar questions and additional content below.Similar questions
- The spoiler, shown in figure 1, will be fitted at the back end of a stock car to give it downforce on the track. The pressure distribution and average shear stress on the top surface are given and the data on the bottom surface can be neglected. The car can reach a maximum speed of 270 km/h on the track. The spoiler has a length and a width of 1.2 m and 0.3 m, respectively. The density of the air is 1.2 kg/m?. Calculate the lift and drag coefficients of the spoiler. Tave = 500 N/m2 P= 1.5 kN/m? P= 0.15 kN/m² U Figure 1arrow_forwardFlow straighteners consist of arrays of narrow ducts placed in a flow to remove swirl and other transverse (secondary) velocities. One element can be idealised as a square box with thin sides as shown below. Calculate the pressure drop across a box with L=22 cm and a= 2.7 cm, if air with free-stream velocity of Uo = 11 m/s flows though the straightener. Use laminar flat-plate theory and take u = 1.85 x 10-5 Pa.s and p = 1.177kg/m³ . %3D %3D a Uo Figure 1: Flow across straighteners.arrow_forwardA semi-cylindrical concrete structure having a radius of 5 m and length of 3 m is rested on ground. Wind (air having a density ρ=1,2 kg/m3 ) at a free-sream speed of 3 m/s with an atmospheric pressure of 100 kPa far upstream the structure blows over the structure. The air entrance to the structure is at ground level corresponding to the forward stagnation point and the magnitude of minimum pressure is acting on the top of the structure a lift force is generated. Estimate the lift coefficient C L =? with calculated magnitude of lift force from potential flow theory ANSWER: 4arrow_forward
- A semi-cylindrical concrete structure having a radius of 3 m and length of 5 m is rested on ground. Wind (air having a density ρ=1,2 kg/m3 ) at a free-sream speed of 10 m/s with an atmospheric pressure of 100 kPa far upstream the structure blows over the structure. The air entrance to the structure is at ground level corresponding to the forward stagnation point and the magnitude of minimum pressure is acting on the top of the structure a lift force is generated. Estimate the lift coefficient C L =? with calculated magnitude of lift force from potential flow theoryarrow_forwardExplain in detail the positioning and environmental impact of large wind turbinesarrow_forwardCalculate the power of the wind at a site that has wind speed of 12 m/s, air density of 1.2 kg/m3. The wind turbine at the site has a rotor diameter of 180 m. What is the maximum power that can be delivered by the wind turbine? (Assume π=3,14)arrow_forward
- A wheel tractor has a 200HP engine.if it is operating at an altitute of 1000m above sea level, at an average temperature of 25 degree celcius, and at an average speed of 12km/hr. Calculate the available rimpull of this tractor. Take rimpull efficiency as 85%arrow_forwardThe energy distribution in the boundary layer over the free of a spliway was observed to be: u/U-(y/8)*0.12 The free stream velocity U is 25m/s and boundary layer thickness 40mm at a certain section. calculate displacement thickness and energy thickness.arrow_forwardAn air current impinges laterally on an isolated train car of dimensions 3 m high, 12.2 m long and 1.8 m deep, with a height above the ground of 0.9 m and a distance between wheels of 1.5 m (As shown below). shown in the figure). Determine the wind speed needed to overturn the car if it has a weight of 178,000 N, CD 1.2. Use free body analysis. Consider the position of the center of gravity. p= 1.22kg/m3 Solution 164km/h U 1.5 m 1.8 m W 12.2 m 1.5 m F 1.5 m 0.9 marrow_forward
- 3. A semi-cylindrical concrete structure having a radius of 5 m and length of 3 m is rested on ground. Wind (air having a density p=1,2 kg/m3 ) at a free-sream speed of 3 m/s with an atmospheric pressure of 100 kPa far upstream the structure blows over the structure. The air entrance to the structure is at ground level corresponding to the forward stagnation point and the magnitude of minimum pressure is acting on the top of the structure a lift force is generated. Estimate the lift coefficient CL =? with calculated magnitude of lift force from potential flow theory Lütfen birini seçin: а. 2 b. 3 С. 1 d. 12 е. 4arrow_forwardDesign the rotor for an aero generator to develop 1000 W at a wind speed of 15 m/s. NACA 4412 airfoil may be used for the rotor. Let us take the design power coefficient as 0.4 and the combined drive train and generator efficiency 0.9. Taking the air density as 1.224 kg/m3arrow_forwardQ4:- If the velocity profile for the laminar boundary layer is given by :- 24 -²)-¹()*+()* ² ( 2 ) - ² ( ² ) ² + ( ²3/ = 2 00 Starting from the integral momentum equation, find an expressions in terms of the Reynolds number to evaluate 1- Boundary Layer Thickness 2-Wall Shear Stress 3- Average Skin Friction Coefficient 4- Drag Force exerted on One Sidearrow_forward
arrow_back_ios
SEE MORE QUESTIONS
arrow_forward_ios
Recommended textbooks for you
- Elements Of ElectromagneticsMechanical EngineeringISBN:9780190698614Author:Sadiku, Matthew N. O.Publisher:Oxford University PressMechanics of Materials (10th Edition)Mechanical EngineeringISBN:9780134319650Author:Russell C. HibbelerPublisher:PEARSONThermodynamics: An Engineering ApproachMechanical EngineeringISBN:9781259822674Author:Yunus A. Cengel Dr., Michael A. BolesPublisher:McGraw-Hill Education
- Control Systems EngineeringMechanical EngineeringISBN:9781118170519Author:Norman S. NisePublisher:WILEYMechanics of Materials (MindTap Course List)Mechanical EngineeringISBN:9781337093347Author:Barry J. Goodno, James M. GerePublisher:Cengage LearningEngineering Mechanics: StaticsMechanical EngineeringISBN:9781118807330Author:James L. Meriam, L. G. Kraige, J. N. BoltonPublisher:WILEY
Elements Of Electromagnetics
Mechanical Engineering
ISBN:9780190698614
Author:Sadiku, Matthew N. O.
Publisher:Oxford University Press
Mechanics of Materials (10th Edition)
Mechanical Engineering
ISBN:9780134319650
Author:Russell C. Hibbeler
Publisher:PEARSON
Thermodynamics: An Engineering Approach
Mechanical Engineering
ISBN:9781259822674
Author:Yunus A. Cengel Dr., Michael A. Boles
Publisher:McGraw-Hill Education
Control Systems Engineering
Mechanical Engineering
ISBN:9781118170519
Author:Norman S. Nise
Publisher:WILEY
Mechanics of Materials (MindTap Course List)
Mechanical Engineering
ISBN:9781337093347
Author:Barry J. Goodno, James M. Gere
Publisher:Cengage Learning
Engineering Mechanics: Statics
Mechanical Engineering
ISBN:9781118807330
Author:James L. Meriam, L. G. Kraige, J. N. Bolton
Publisher:WILEY
Heat Transfer – Conduction, Convection and Radiation; Author: NG Science;https://www.youtube.com/watch?v=Me60Ti0E_rY;License: Standard youtube license