Air flows in a horizontal cylindrical duct of diameter D = 100 mm. At a section a few meters from the entrance, the turbulent boundary layer is of thickness δ1 = 5.25 mm, and the velocity in the inviscid central core is U1 = 12.5 m/s. Farther downstream the boundary layer is of thickness δ2 = 24 mm. The velocity profile in the boundary layer is approximated well by the
Want to see the full answer?
Check out a sample textbook solutionChapter 9 Solutions
FOX+MCDONALD'S INTRO.TO...-ACCESS+BOX
Additional Engineering Textbook Solutions
Statics and Mechanics of Materials (5th Edition)
INTERNATIONAL EDITION---Engineering Mechanics: Statics, 14th edition (SI unit)
Heating Ventilating and Air Conditioning: Analysis and Design
Engineering Mechanics: Dynamics (14th Edition)
Degarmo's Materials And Processes In Manufacturing
- 1.)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 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 . Since the magnitude of minimum pressure is acting on the top of the structure determine the magnitude of lift force due to the pressure difference in vertical direction .Assume flow potential ANSWER: 648 Narrow_forwardAirstream flows in a converging duct from a cross-sectional area A1=50cm2to across-sectional area A2=40cm2. If T1=300K, P1=100kPa, and V1=100m/s, find M2, P2,and T2.arrow_forwardConsider two different flows over geometrically similar airfoil shapes,one airfoil being twice the size of the other. The flow over the smallerairfoil has freestream properties given by T∞ = 200 K, ρ∞ = 1.23 kg/m3,and V∞ = 100 m/s. The flow over the larger airfoil is described byT∞ = 800 K, ρ∞ = 1.739 kg/m3, and V∞ = 200 m/s. Assume thatboth μ and a are proportional to T 1/2. Are the two flows dynamicallysimilar?arrow_forward
- Air flows through the test section of a small wind tunnel at speed V = 7.5 ft/s. The temperature of the air is 80°F, and the length of the wind tunnel test section is 1.5 ft. Assume that the boundary layer thickness is negligible prior to the start of the test section. Is the boundary layer along the test section wall laminar or turbulent or transitional?arrow_forwardThe gases coming out of the steam boiler are discharged from a chimney with a rectangular area of 15x20 ft at a constant speed of 50 ft / s. The flue line is 250 ft long and there are 2 bends at 90 degrees. The temperature of the gases is constant at 180 F and an average pressure of 1 atm. Its physical properties are the same as the air in the same conditions. Calculate the pressure difference and required power in the flue line.arrow_forward1.A.)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 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 . Determine the magnitude of pressure at ground level in terms of gage .Assume flow potential ANSWER: 5,4 Pa 1.B.)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 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 . Since the magnitude of minimum pressure is acting on the top of the structure determine the magnitude of lift force due to the pressure difference in…arrow_forward
- Air is flowing parallel to the plate at U∞=5 m/s and T∞=300 K over the flat plate of length L=0.1 m anddepth of 1 m into the paper, at the atmospheric pressure at the same temperature as the plate. Find;a) Boundary layer thickness at the point x = L of the plateb) Find the total resistance force acting on the two surfaces of the plate.c) The velocities in the hydrodynamic boundary layer are measured by a hot wire anomemeter. Thevelocity at x=0.1 m on the x component is measured as u=3 m/s. Find the distance from the plate and they component of velocity v.arrow_forwardConsider the isentropic flow over an airfoil. The freestream conditionscorrespond to a standard altitude of 10,000 ft and M∞ = 0.82. At a givenpoint on the airfoil, M = 1.0. Calculate p and T at this point.arrow_forwardConsider the same Lockheed F-104 supersonic fighter shown, with the same flight conditions of Mach 2 at an altitude of 11 km. For these conditions the wing angle of attack is α = 0.035 rad = 1.98◦. Assume the chord length of the airfoil is 2.2 m, which is approximately the mean chord length for the wing. Also, assume fully turbulent flow over the airfoil. Calculate: (a) the airfoil skin friction drag coefficient, and (b) the airfoil wave-drag coefficient. Compare the two values of drag.arrow_forward
- We are testing a flat plate of length L = 1.125 m and width W = 0.225 m in a stream of air flowing with a velocity of 20 m/s. In test case 1, the air is flowing parallel to L and in test case 2 air is flowing parallel to W. Find: What portion of the boundary layer flow is laminar in each case? What is the highest laminar boundary layer thickness in each case? Assuming the flow is entirely turbulent over the plate, calculate the drag force in both test cases Take air density as 1.2 kg/m3 and its viscosity as μ=18×10−6μ=18×10−6 N.s/m2.arrow_forwardThe purpose of this problem is to give you a feel for the magnitude ofReynolds number appropriate to real airplanes in actual flight. a. Consider the DC-3 shown in (1.1). The wing root chord length(distance from the front to the back of the wing where the wing joinsthe fuselage) is 14.25 ft. Consider the DC-3 flying at 200 miles perhour at sea level. Calculate the Reynolds number for the flow over thewing root chord. (This is an important number, because as we will seelater, it governs the skin-friction drag over that portion of the wing.)b. Consider the F-22 shown in (1.5), and also gracing the cover ofthis book. The chord length where the wing joins the center body is21.5 ft. Consider the airplane making a high-speed pass at a velocityof 1320 ft/s at sea level (Mach 1.2). Calculate the Reynolds number atthe wing root.arrow_forwardA converging nozzle having an exit diameter of 30 mmmm is connected to the large tank (Figure 1). The absolute pressure outside the tank is 102 kPakPa. Figure 1 of 1 Part A If the temperature of the air in the tank is 20∘C∘C and the absolute pressure is 280 kPakPa, determine the mass flow from the tank.arrow_forward
- 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