An automobile has a characteristic length and area of 8ft and 60 ft, respectively. When tested in sea-levelstandard air, it has the following measured drag forceversus speed:V, mi/h20 | 4060Drag, Ibf31115249The same car travels in Colorado at 65 mi/h at an altitudeof 3500 m. Using dimensional analysis, estimate (a) itsdrag force and (b) the horsepower required to overcomeair drag.

The properties of air at sea level are: The Reynolds number is The drag coefficient is Velocity…

Answered: An automobile has a characteristic…

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

The speed of sound c in an ideal gas is known to be a function of the ratio of specific heats k, absolute temperature T, and specific ideal gas constant Rgas. Showing all your work, use dimensional analysis to find the functional relationship between these parameters.
20 4. An airship is to operate at 20 m/s in air at standard conditions (p 1.225 kg/m³, p 101,300 Pa). A model is constructed to scale and tested in a variable-pressure wind tunnel at the same air temperature to = determine the drag. GOOD YEAR The Goodyear Blimp is an example of an airship. (a) What criterion should be used to determine dynamic similarity? (You may assume that roughness is not important for this problem.) (b) If the model is tested at 20 m/s, what pressure should be used in the wind tunnel? (c) If the model drag force is found to be 250 N, what will be the drag of the full-scale airship?
The drag force on a submarine, which is moving on the surface, is to be determined by a test on a model which is scaled down to one-twentieth of the prototype. The test is to be carried in a towing tank, where the model submarine is moved along a channel of liquid. The density and the kinematic viscosity of the seawater are 1010 kg/m³ and 1.3x10-6 m 2/s, respectively. The speed of the prototype is 2.6 m/s. Assume that F = f(V, L. g. p.), using pi-theorem and similarity principle to: a) Determine the speed at which the model should be moved in the towing tank. b) Determine the kinematic viscosity of the liquid that should be used in the towing tank.
A one-fiftieth-scale model of a military airplane is tested at1020 m/s in a wind tunnel at sea-level conditions. Themodel wing area is 180 cm 2 . The angle of attack is 3 ° . If themeasured model lift is 860 N, what is the prototype lift,using Mach number scaling, when it flies at 10,000 m standardaltitude under dynamically similar conditions? Note:Be careful with the area scaling.
The aerodynamic drag of a new sports car is to be predicted at a speed of 60.0 mi/h at an air temperature of 25°C. Automotive engineers build a one-third scale model of the car to test in a wind tunnel. The temperature of the wind tunnel air is also 25°C. The drag force is measured with a drag balance, and the moving belt is used to simulate the moving ground (from the car’s frame of reference). Determine how fast the engineers should run the wind tunnel to achieve similarity between the model and the prototype.
The drag force (Fdrag) exerted by air on a moving car depends on a dimensionless drag coefficient (Carag), the specific volume of air (Vair), the velocity of the car (Var), and the frontal area of the car (Afront). (a) Based on unit considerations alone, obtain an equation for the drag force. Be sure to explicitly demonstrate that the final units are correct. (b) Explain, based on your equation, what happens to the drag force when each variable is changed in isolation. Indicate whether this predicted behaviour matches your intuition in each case.
HELPPPPPP URGENTTTTTT!!!
A uniform stream overflows in a circular cylinder and then a periodic Kármán vortex street is created. Through repeating variables, how can I create a dimensionless relationship for Kármán vortex shedding frequency (fk), where free-stream speed is V, fluid density is p, fluid viscosity is μ, and cylinder's diameter is d?
A football, meant to be thrown at 60 mi/h in sea-level air( ρ = 1.22 kg/m 3 , μ = 1.78 E-5 N . m 2 ), is to be testedusing a one-quarter scale model in a water tunnel ( ρ =998 kg/m 3 , μ = 0.0010 N . s/m 2 ). For dynamic similarity,what is the ratio of prototype force to model force?( a ) 3.86 : 1, ( b ) 16 : 1, ( c ) 32 : 1, ( d ) 56 : 1, ( e ) 64 : 1
1. (a) The motion of a floating vessel through the surrounding fluid results in a drag force D which is thought to depend upon the vessel's speed v, its length I, the density p and dynamic viscosity μ of the fluid and the acceleration due to gravity g. Show that:- D = pv²1² (1) (b) In order to predict the drag on a full scale 50m long ship traveling at 7m/s in sea water at 5°C of density 1027.7225 kg/m³ and viscosity 1.62 x 103 Pa.s, a model 3m long is tested in a liquid of density 805 kg/m³. What speed does the model need to be tested at and what is the required viscosity of the liquid?
The drag on a 2-m-diameter satellite dish due to an 69-km/hr wind is to be determined through a wind tunnel test using a geometrically similar 0.4-m-diameter model dish. Assume standard air for both model and prototype. (a) At what air speed should the model test be run? (b) With all similarity conditions satisfied, the measured drag on the model was determined to be 152 N. What is the predicted drag on the prototype dish? (a) Vm = (b) D = i i km/hr N
Buckingham Pi. A mechanical stirrer is used to mix chemicals in a large tank. The required shaft power P is a function of liquid density p, viscosity μ, stirrer blade diameter D, and angular speed w of the spinning blades. (a) use repeating variables p, D, u to find a relation between dimensionless power (1) and w (m2); (b,c) a small 1/3 scale model is used in water to predict the actual required power in a viscous liquid with SG =2 and μ = 12μwater. Find (b) the ratio of speeds, wwater/ wactual, necessary for dynamic similarity and then (c) the predicted ratio of powers Pwater/ Pactual. expecting unit : (a) π1 ~ D ; π^2 ~ D^2; (b) wwater/ wactual: 10^0; (c) Pwater/ Pactual 10^-3 SI constant Patm = 10^5 Pa; pwater - 1000 kg/m^3; pair ~ 1.2kg/m^3; µwater ~ 10^-3 N•s/m^2; pair - 2 x 10^-5 N•s/m^2 ; g = 9.8 m/s^2 =

Recommended textbooks for you

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

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

SEE MORE TEXTBOOKS