(Review experimental scaling) A lightweight parachute is being designed for military use. Its diameter D is 20 ft and the total weight W of the falling payload, parachute, and equipment is 190 lb. The design terminal settling speed V. (or terminal velocity) of the parachute at this weight is 16 ft/'s. A one-twelfth scale model of the parachute is tested in a wind tunnel. The wind tunnel temperature and pressure are the same as those of the prototype, which is 70 °F and standard atmospheric pressure. a) Calculate the drag coefficient of the prototype. (Hint: At terminal velocity, speed is constant so weight is in equilibrium with aerodynamic drag.) b) At what speed should the wind tunnel be run in order to achieve dynamic similarity? c) Find the aerodynamic drag force of the model parachute in the wind tunnel in pounds.

(Review experimental scaling) A lightweight parachute is being designed for military use. Its diameter D is 20 ft and the total weight W of the falling payload, parachute, and equipment is 190 lb. The design terminal settling speed V. (or terminal velocity) of the parachute at this weight is 16 ft/'s. A one-twelfth scale model of the parachute is tested in a wind tunnel. The wind tunnel temperature and pressure are the same as those of the prototype, which is 70 °F and standard atmospheric pressure. a) Calculate the drag coefficient of the prototype. (Hint: At terminal velocity, speed is constant so weight is in equilibrium with aerodynamic drag.) b) At what speed should the wind tunnel be run in order to achieve dynamic similarity? c) Find the aerodynamic drag force of the model parachute in the wind tunnel in pounds.

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 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.
A flow model is constructed to a scale of 1/23 of the prototype and the free stream velocity in the prototype is 3 that of the model. Calculate the following ratios between prototype and model: (Provide your answer to two decimal places) The time ratio f, = The acceleration ratio a, =
I need answer 2,3 and i give upvote (no plagarism)
A light parachute for military purposes is being designed. Its diameter is 7.3 m, test load, parachute and rig weight is 1023 N. For this weight, the limit descent speed Vt = 6.1 m / s, which is taken as a basis in the design of the parachute. The 1/12 scale model will be tested in the wind tunnel and the temperature and pressure of the tunnel are the same as that of the prototype. (15.5 ºC and standard atmospheric pressure) a) Calculate the resistance coefficient of the prototype. (Hint: At the limit descent speed, the weight is balanced by the aerodynamic resistance.) b) At what speed should the wind tunnel be run to achieve dynamic similarity? c) Calculate the aerodynamic resistance of the model parachute in the wind tunnel. Density of air at 15.5 ºC and standard atmospheric pressure ρ = 1.22 kg / m3 viscosity, µ = 8.16x10-6 kg / m.s will be taken.
This exercise is part of a series of problems aimed at modeling a situation by progressively refining our model to take into account more and more parameters. This progressive approach is very close to what professional scientists do! context We want to lower a suspended load in a controlled way so that it hits the ground with a speed whose modulus is not too great. To slow down the descent, a spring has been added behind the mass (A), The suspended load (B) is connected by a rope passing through a pulley to this mass (A), which slides on a horizontal surface with friction. Information The masses of the charges A and B are known.The mass of the rope itself is negligible (very small compared to the loads).The pulley has negligible mass and can rotate without friction.The charge B is initially stationary and is at a known height h.The surface on which mass A sits is tilted upwards at a known angle theta from the horizontal.There is friction under mass A: the kinetic friction…
A 1:7 scale model simulates the operation of a large turbine that is to generate200 kW with a flow rate of 1.5 m3/s. What flow rate should be used in the model, andwhat power output is expected?(a) Water at the same temperature is used in both model and prototype.(b) The model water is at 25°C and the prototype water is at 10°C.
Drop-load (I)This exercise is part of a series of problems aimed at modeling a situation by progressively refining our model to take into account more and more parameters. This progressive approach is very close to what professional scientists do! context We want to lower a suspended load in a controlled way, so that it hits the ground with a speed whose modulus is not too great. To do this, the suspended load (B) is connected by a rope passing through a pulley to another mass (A), which can move on a horizontal surface. To slow down the descent, we added a spring behind the mass (A). Information The masses of the charges A and B are known.The mass of the rope itself is negligible (very small compared to the loads).The pulley has negligible mass and can rotate without friction.The charge ? is initially stationary and is at a known height h.The surface on which mass A is placed is horizontal.There is no friction between mass A and the surface on which it is placed.The string attached…
Drop-load (I)This exercise is part of a series of problems aimed at modelling a situation by progressively refining our model to consider more and more parameters. This progressive approach is very close to what professional scientists do! Context We want to lower a suspended load in a controlled way so that it hits the ground with a speed whose modulus is not too great. To do this, the suspended load (B) is connected by a rope passing through a pulley to another mass (A), which can move on a horizontal surface. Information The masses of the charges A and B are known.The pulley is a ring of mass mp and radius R that can rotate without friction.The surface on which mass A is placed is horizontal.There is no friction between mass A and the surface on which it is placed.The string attached to mass A is perfectly parallel to the surface on which the mass rests. SchematizationDraw a diagram of each object that interests us. Draw x- and y-axes for each object. Draw and name each force…
2 A prototype car is designed for cold weather operation in Denver (-10°C, 83 kPa, altitude 1600m, µ = 1.741 × 10-5 Pas). It's drag force is to be tested in a 1:7 model in a wind tunnel at 150 mph under standard sea level conditions. If the model and prototype satisfy dynamic similarity what prototype velocity, in mph, is matched? Is this a reasonable test? 1 mile = 1609 m HINT: p = pRT
A small model water turbine is tested in a flume where Cp is measured to be 0.38. Assuming dynamic similarity exists, calculate the power output of a full-size turbine of diameter 12 m operating in a tidal stream, where the water density is 1030 kg/m³, μ = 1.307-³ Ns/m² and maximum water velocity of 2.2 m/s.
Problem 3: Let's say you want to predict the aerodynamic drag of a new car based on the use of a model that is one- fifth scale of the actual car/prototype car. We want to predict the drag of the car when it has wind velocity 75 miles/hour with an air temperature of 40°C. The model is placed in a wind tunnel at 10°C. Determine the wind tunnel velocity necessary to achieve similarity between the model and the prototype.
1. A model submarine is tested in a sea water tank at a speed of 30 m/s. The prototype speed should be 21.6 km/hr. (a) Determine the geometric scale between the model and the prototype (b) Determine the model speed if it is tested in a pressurized air wind tunnel with 12/s. kinematic viscosity v = 8 × 10-7 m² /s. For sea water use v = 1.124 × 10-6 m² /s.