Calculate the values of the Rx for the two parts of Example 17.1 shown below. Boundary layers on flat plates are laminar only up to RX 3.5 105 to 2.8 106. Are these values exceeded for the boundary layers in Example 17.1? Example 17.1. Calculate the boundary-layer thickness for: (a) A point on an airplane wing 2 ft from the leading edge, when the plane is flying 200 mi/h through air. (b) A point 2 ft from the bow of a ship, when the ship is moving 10 mi/h through water. For the airplane and for the ship 8=5. 1.61-10-4 ft²/s-2 ft 200 mi/h 5280 ft/mi h/3600 s = 5.24-10 ft = 0.063 in = 1.60 mm 1.08-10-5 ft²/s-2 ft 10 mi/h 5280 ft/mi- h/3600 s = 6.06 10³ ft=0.073 in = 1.8 mm 8=5. 1/2 1/2

Calculate the values of the Rx for the two parts of Example 17.1 shown below. Boundary layers on flat plates are laminar only up to RX 3.5 105 to 2.8 106. Are these values exceeded for the boundary layers in Example 17.1? Example 17.1. Calculate the boundary-layer thickness for: (a) A point on an airplane wing 2 ft from the leading edge, when the plane is flying 200 mi/h through air. (b) A point 2 ft from the bow of a ship, when the ship is moving 10 mi/h through water. For the airplane and for the ship 8=5. 1.61-10-4 ft²/s-2 ft 200 mi/h 5280 ft/mi h/3600 s = 5.24-10 ft = 0.063 in = 1.60 mm 1.08-10-5 ft²/s-2 ft 10 mi/h 5280 ft/mi- h/3600 s = 6.06 10³ ft=0.073 in = 1.8 mm 8=5. 1/2 1/2

Elements Of Electromagnetics

7th Edition

ISBN:9780190698614

Author:Sadiku, Matthew N. O.

Publisher:Sadiku, Matthew N. O.

ChapterMA: Math Assessment

Section: Chapter Questions

Problem 1.1MA

See similar textbooks

Similar questions

On a hot day (T = 30°C), a truck moves along the highway at 29.1 m/s. The flat side of the truck is treated as a simple, smooth flat–plate boundary layer, to first approximation. Estimate the x-location along the plate where the boundary layer begins to transition to turbulence. How far downstream from the beginning of the plate do you expect the boundary layer to become fully turbulent? Give both answers to one significant digit.
The main cross-cable between towors of a coastal suspension bridge is 27.9 cm in diameter and 60 m long. Estimate the total drag force in (N] on this cable in crosswinds of 67.5 km/h. Assume the temperature of air is 15°C. Assume the drag coefficient is 1.5. The tolerance of your answer is 2%. PROPERTIES Air at 15"C Density = 123 kglm Dynamic viscosity 1.79 x 10 Ns/m?
1. In the figure shown below, choose whether the statement is true or false (Please justify your answer) (a) At a give x-location, if Re were to increase, the boundary layer thickness would decrease. (b) As upstream velocity decreases, so does the boundary layer thickness (c) As the kinematic viscosity increases, so does the boundary layer thickness (d) As the fluid density decreases, so does the boundary layer thickness (e) As the x-location increases, so does the boundary layer thickness
A wind tunnel is being used to study the aerodynamics of a full-scale model rocket that is 30 cm long. Scaling for drag calculations are based on the Reynolds number. The rocket hasan expected maximum velocity of 190 km/h. What is the Reynolds number at this speed? Assume ambient air is at 20°C. The wind tunnel is capable of speeds up to 160 km/h; so an attempt is made to improve this top speed by varying the air temperature. Calculate the equivalent speed for the wind tunnel using air at 5°C and 65°C. Would replacing air with carbon dioxide provide higher equivalent speeds?
Question 3 The aerodynamic derivative X, may be determined from the following expression: X -pU SCD %3D where p is the air density, S is the wing area, U is the airspeed, and Cp is the drag coefficient. Consider an aircraft of weight 68 kN and wing area 43 m?, flying straight and level under international standard atmosphere (ISA) conditions, where p 1.018 kg/m, at an airspeed of 155 m/s. The aircraft %3D has a drag polar Cp = 0.011 + where Ci is the lift coefficient. Calculate the value of X, at this flight condition. Give your answer in units of Ns/m.
Reference 12 contains inviscid theory calculations for the upper and lower surface velocity distributions V(x) over an airfoil, where x is the chordwise coordinate. A typical re- sult for small angle of attack is as follows: xlc VIU„(upper) VIU„(lower) 0.0 0.0 0.0 0.025 0.97 0.82 0.05 1.23 0.98 0.1 1.28 1.05 1.13 0.2 1.29 0.3 1.29 1.16 0.4 1.24 1.16 0.6 1.14 1.08 0.8 0.99 0.95 1.0 0.82 0.82 Use these data, plus Bernoulli's equation, to estimate (a) the lift coefficient and (b) the angle of attack if the airfoil is symmetric.
Help me please
Mention the name of a technique which can be used to control the boundary layer
Some engineers want a good estimate of drag and boundary-layerthickness at the trailing edge of a miniature wing. The chord and span ofthe wing are 6 mm and 30 mm, respectively and a typical flight speed is5 m/s in air (kinematic viscosity = 15 × 10−6 m2/s; density = 1.2kg/m3). An engineer may decide to make a superseding model withchord and span of 150 mm and 750 mm, respectively. Measurements onthe model in a water channel flowing at 0.5 m/s (kinematic viscosity = 1× 10−6 m2/s, density = 1000 kg/m3) give a drag of 0.19 N and aboundary-layer thickness of 3 mm. Estimate the corresponding values forthe prototype
The large block shown is x = 72 cm wide, y = 54 cm long, and z = 9.0 cm high. This block is passing through air (density of air p = 1.43 kg/m³) at a speed of v = 8.61 m/s. Find the drag force F41 acting on the block when it has the velocity vj and a drag coefficient I = 0.812. V2 Fa.1 N %3D Find the drag force F42 acting on the block when it has the velocity vz with a drag coefficient I = 0.893. F42 N Find the drag force Fa.3 acting on the block when it has the velocity vz with a drag coefficient I = 1.06. F4.3 = N EN
Two definitions of displacement thickness are given in this chapter. Write both definitions in your own words. For the laminar boundary layer growing on a flat plate, which is larger—boundary layer thickness ? or displacement thickness ?*? Discuss.
Consider again a semi truck traveling at 55 mph on the freeway. The ambient air is at 1 atm and 80F. The trailer of the truck can be considered as a 8-ft-wide, 10-ft-high, 48-ft-long rectangular box. Assuming flat plate boundary layer behavior and no flow separation, estimate the drag force acting on the top and side surfaces and the power [hp] required to overcome this drag. Does the analysis seem reasonable for the actual drag force for the truck? Explain.