A one-fourth scale model of an airplane is to be tested in water. The airplane has a velocity of 700 km/h in air at −50°C. The water temperature in the test section is 10°C. In order to achieve similarity between the model and the prototype, the test is done at a water velocity of 393 km/h. The properties of air at 1 atm and −50°C: ? = 1.582 kg/m3, ? = 1.474 × 10−5 kg/m·s. The properties of water at 1 atm and 10°C: ? = 999.7 kg/m3, ? = 1.307 × 10−3 kg/m·s. If the average drag force on the model is measured to be 13,800 N, the drag force on the prototype is (a) 590 N (b) 862 N (c) 1109 N (d ) 4655 N (e) 3450 N

A one-fourth scale model of an airplane is to be tested in water. The airplane has a velocity of 700 km/h in air at −50°C. The water temperature in the test section is 10°C. In order to achieve similarity between the model and the prototype, the test is done at a water velocity of 393 km/h. The properties of air at 1 atm and −50°C: ? = 1.582 kg/m3, ? = 1.474 × 10−5 kg/m·s. The properties of water at 1 atm and 10°C: ? = 999.7 kg/m3, ? = 1.307 × 10−3 kg/m·s. If the average drag force on the model is measured to be 13,800 N, the drag force on the prototype is (a) 590 N (b) 862 N (c) 1109 N (d ) 4655 N (e) 3450 N

Principles of Heat Transfer (Activate Learning with these NEW titles from Engineering!)

8th Edition

ISBN:9781305387102

Author:Kreith, Frank; Manglik, Raj M.

Publisher:Kreith, Frank; Manglik, Raj M.

Chapter5: Analysis Of Convection Heat Transfer

Section: Chapter Questions

Problem 5.70P

See similar textbooks

Similar questions

While preparing an experiment of a scale model submarine in a wind tunnel, for conditions of dynamic similarity, it is calculated that the wind speed is required to be 120 m/s. Which one of the following options will not help to reduce the air velocity of the wind tunnel? A) Lowering the design velocity of the prototype (full scale) submarine B) Increasing the pressure of the air used in the wind tunnel c) Increasing the size of the scale model D) Decreasing the density of air used in the wind tunnel E) Reducing the temperature of the air used in the wind tunnel
A 1:20 scaled-down model of a hydrofoil is tested in a water channel, at a velocity of 0.179 m/s. At this velocity, a drag force of 2.2 N is measured. Determine the drag force of the original hydrofoil, at a velocity of 0.8 m/s.
FLUID MECHANICS 0.5m by 2m flat thin plate is moved at 5m/s on a 2-mm thick layer of SAE30 oil at 38 degrees Celsius that separates it from a flat surface. The velocity distribution between the plate and the surface is assumed to be linear. What force is required if the plate and surface are horizontal? (μSAE30 = 0.1 N-s/m2)
Consider a Lear jet flying at a velocity of 250 m/s at an altitude of 10 km,where the density and temperature are 0.414 kg/m3 and 223 K,respectively. Consider also a one-fifth scale model of the Lear jet beingtested in a wind tunnel in the laboratory. The pressure in the test section ofthe wind tunnel is 1 atm = 1.01 × 105 N/m2. Calculate the necessaryvelocity, temperature, and density of the airflow in the wind-tunnel testsection such that the lift and drag coefficients are the same for thewind-tunnel model and the actual airplane in flight.
A ship 350 m long moves in sea water whose density is 1030 kg/m3 . A 1:120 model of this ship is to be tested in a wind tunnel. The velocity of the wind tunnel around the model is 35 m/s and the resistance of the model is 65 N. Determine the velocity and also the resistance of the ship in sea water. The density of air is given as 1.24 kg/m3 . Take the kinematic viscosity of air and sea water as 0.012 stokes and 0.018 stokes respectively.
What is used as a similarity parameter to help determine whether the flow in a body and its scaled version are aerodynamically similar? Similarity Coefficient Mach Number Skin Friction Drag Coefficient Reynolds Number Thank you.
An air hockey puck has a mass of 50 g and is 9 cm in diameter. When placed on the air table, a 40 degrees C air film, of thickness 0.12 mm-thickness forms under the puck. a) Using Sutherlands law, what is the viscosity of the air? b) If the puck is travelling at 10 m/s, assuming a linear velocity profile, what is the force on the puck due to shear stress? c)What is the terminal velocity of the puck?
A square block weighing 1.1 KN and 250 mm on an edge slides down an 20 degrees inclined on a film of oil 6.0 micrometer thick. Assuming a linear velocity profile in the oil, what is the terminal speed of the block in m/s. The viscosity of the oil is 7 mPa-s. a.5.16 b.5.62 c.5.75 d.5.48
Although we usually think of a model as being smaller than the prototype, describe at least three situations in which it is better for the model to be larger than the prototype.
Which choice is not a scaling parameter used to nondimensionalize the equations of motion? (a) Characteristic length, L (b) Characteristic speed, V (c) Characteristic viscosity, ? (d ) Characteristic frequency, f (e) Gravitational acceleration, g
Consider the common situation in which a researcher is trying to match the Reynolds number of a large prototype vehicle with that of a small-scale model in a wind tunnel. Is it better for the air in the wind tunnel to be cold or hot? Why? Support your argument by comparing wind tunnel air at 10°C and at 45°C, all else being equal.
q1(c) A 20 × 20 cm cubical block slides on an oil surface over the inclined plane at 20° horizontal. Steady state velocity is 0.4 m/s. The thickness of the oil film between the block and the surface is 0.4 mm, and the mass of the block is 6.52 kg. (i) Illustrate the free body diagram for the above condition. (ii) Calculate the kinematic viscosity of the oil if the specific gravity of the oil that you choose must be in the range between 0.78 to 0.86.