You are tasked to design a parachute with the following requirements: Weight of falling payload = 981 N (100 kg) Diameter = 7.5 m Terminal velocity = 6 m/s The parachute is expected to be used in a typical environment of 15°C and atmospheric pressure. If you are to create a one-tenth scale model of the parachute to be tested in a wind tunnel under the same conditions, a) Calculate the drag coefficient of the prototype and b) Determine the speed by which the wind tunnel should be run to achieve dynamic similarity. Hint: Cp P' P

You are tasked to design a parachute with the following requirements: Weight of falling payload = 981 N (100 kg) Diameter = 7.5 m Terminal velocity = 6 m/s The parachute is expected to be used in a typical environment of 15°C and atmospheric pressure. If you are to create a one-tenth scale model of the parachute to be tested in a wind tunnel under the same conditions, a) Calculate the drag coefficient of the prototype and b) Determine the speed by which the wind tunnel should be run to achieve dynamic similarity. Hint: Cp P' P

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.

Chapter6: Forced Convection Over Exterior Surfaces

Section: Chapter Questions

Problem 6.32P

See similar textbooks

Similar questions

A paramecium is an elongated unicellular organism with approximately 50 μmin diameters and 150 μmin lengths. It swims through water by whip-like movements of cilia, small hairs on the outside of its body. Because it moves "head first" through the water, drag is determined primarily by its diameter and only secondarily by its length, so it's reasonable to model the paramecium as a 70-μm diameter sphere. A paramecium uses 2.0 PW of locomotive power to propel itself through 20∘C water, where 1 pW = 1 picowatt = 10−12W. What is its swimming speed in μm/s? Express your answer in micrometers per second.
a test tank will be used to measure the drag of a scale model ship 0.8 m long. This model bears full resemblance to a 40 m long prototype ship that was designed to sail at a speed of 10 m / s. a) model speed b) the ratio between model and prototype drag windows c) a ratio between the powers needed to overcome the drag of the model and the prototype take the number of froud into account in your analysis.
1:25 scale model of a submarine is tested at 180 ft/s in a wind tunnel using sea-level standard air. What is the prototype speed in seawater at 20°C for dynamic similarity? If the model drag is 1.6lb, what is the prototype drag?
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.
A student team is to design a human-powered submarine for a design competition. The overall length of the prototype submarine is 95 (m), and its student designers hope that it can travel fully submerged through water at 0.440 m/s. The water is freshwater (a lake) at T = 15°C. The design team builds a one-fifth scale model to test in their university’s wind tunnel. A shield surrounds the drag balance strut so that the aerodynamic drag of the strut itself does not influence the measured drag. The air in the wind tunnel is at 25°C and at one standard atmosphere pressure. At what air speed do they need to run the wind tunnel in order to achievesimilarity?
(COLLAB) Simulate projectile motion with air resistance in PhysLab. A shuttlecock is launched from the ground with an initial speed of 36.9688 m/s at an angle of 6.8583 degrees with respect to the horizontal. The shuttlecock experiences air resistance with a drag coefficient of 0.1931 in an environment where the air density is 0.9453 kg/m3. If the shuttlecock has a radius of 3.4 cm and a mass of 5.2 grams, what is the maximum height reached by the shuttlecock? Assume that the experiment is done near the surface of the earth (initHeight = 0) .
(a) Discuses three necessary conditions for complete similarity between a model and a prototype in dimensional analysis. (b) In the design and development competition in a University, a team of students has planned to develop a prototype of submarine that would travel fully submerged at a certain speed in a fresh lake water. The team has designed a model which has one-sixth of a prototype size to test in the university wind tunnel to study the effect of various parameters.What will happen to the length of the model if the temperature of the blowing wind increases as a result of the season change in summer compared to winter?Considering the necessary assumptions discuss the reason.
Find the velocity (m/s) at which test should be run in a wind tunnel on a model wing of 11 cm chord in order that RN. shall be the same as for a wing with a 1.16 m chord at 41.4 m/s. Air under standard conditions in both cases. Round-off answer to the nearest hundredths.
List and describe the three necessary conditions for complete similarity between a model and a prototype.
A 1:30 model of a ship is made. The real ship has a hull length of 130 m and travels at 7.9 m/s. Find the fraude number. If there is a dynamic similarity and froude # criterion applies, what should the velocity of the mdoel ship be?
Here, there is a human powered submarine. The length of the submarine is 4.85 m and the hope is it can travel fully submerged through water at 0.440 m/s. The water it is being tested in is freshwater at a Temperature of 15 degrees celcius. The submarine model is built on a 1/5 scale and is built in a wind tunnel. A shield surrounds the drag balance strut so that the aerodynamic drag of the strut itself does not influence the measured drag. Here, the wind in the wind tunnel is at 25°C and at one standard atm pressure. What air speed is needed to run the wind tunnel in order to achieve similarity?
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.