You are to conduct wind tunnel testing of a new football design that has a smaller lace height than previous designs. It is known that you will need to maintain a Re and St similarity for the testing. Based on standard college quarterbacks, the prototype parameters are set at V = 40 mph and ω = 300 rpm, where V and ω are the speed and angular velocity of the football. Theprototype football has a 7 in. diameter. Due to instrumentation required to measure pressure and shear stress on the surface of the football, the model will require a length scale of 2:1 (the model will be larger than the prototype). Determine the required model freestream velocity and modelangular velocity. [Answer in units of mph and rpm].

Question
Asked Nov 8, 2019
83 views
You are to conduct wind tunnel testing of a new football design that has a smaller lace height than previous designs. It is known that you will need to maintain a Re and St similarity for the testing. Based on standard college quarterbacks, the prototype parameters are set at V = 40 mph and ω = 300 rpm, where V and ω are the speed and angular velocity of the football. The
prototype football has a 7 in. diameter. Due to instrumentation required to measure pressure and shear stress on the surface of the football, the model will require a length scale of 2:1 (the model will be larger than the prototype). Determine the required model freestream velocity and model
angular velocity. [Answer in units of mph and rpm].
check_circle

Expert Answer

Step 1

Determine the length scale ratio of model prototype;

help_outline

Image Transcriptionclose

DR D 2:1 2 1 Di D 2D

fullscreen
Step 2

For same air conditions:

Determine the required model free stream velocity using the formula;

help_outline

Image Transcriptionclose

V= V 1 VV 2 (40 mph) V 2 = 20 mph

fullscreen
Step 3

Determine the angular velocity of the model using the Strou...

help_outline

Image Transcriptionclose

(st)(St), D V OD V V V,D D V 20 300 240 75rpm

fullscreen

Want to see the full answer?

See Solution

Check out a sample Q&A here.

Want to see this answer and more?

Solutions are written by subject experts who are available 24/7. Questions are typically answered within 1 hour.*

See Solution
*Response times may vary by subject and question.
Tagged in

Engineering

Civil Engineering

Related Civil Engineering Q&A

Find answers to questions asked by student like you
Show more Q&A
add
question_answer

Q: Fluid Mechanics, Euler's Equation: The closed tank shown in the image is full of liquid with a speci...

A: To determine: The pressure difference, PC- PA and PB- PA.

question_answer

Q: The offset link has a width of w=200mm and a thickness of 40mm. The allowable normal stress is 80 MP...

A: Find the area of the offset link for the link width of 200 mm and thickness of 40 mm.

question_answer

Q: Fluid mechanics, pipe problem: The pipe shown has a 180o vertical bend in it. The diameter, D, is 1 ...

A: Determine the density of water using the relation;

question_answer

Q: bolteo 2.9) Two structunal members Band C are to bracket A. knowing that both members are ih tension...

A: To determine: The magnitude and direction of the resultant force.Parallelogram lawTriangle rule.

question_answer

Q: The overhangin beam is supported by a pin at A and roller at B. The beam supports the distributed lo...

A: Draw the free body diagram of the given beam as in Figure (1).

question_answer

Q: How do I approach part c? Would the reaction at C not depend on where the spring is mounted and ther...

A: c)The spring force transmitted at any point in it. Hence, the spring force acts at point C is equal ...

question_answer

Q: 8.129 The rectangular plate is subjected to the pressure P Po-cos 2b Determine the resultant force o...

A: It is required to calculate the resultant force of pressure and co-ordinates of point of application...

question_answer

Q: The cable is subjected to a 150-lb horizontal force at B, and an 80-lbvertical force at C. Determine...

A: Sketch the free body diagram of the system.

question_answer

Q: Fluid Mechanics: Laminar flow occurs between two horzontal parallel plates under a pressure gradient...

A: Part AIt is given that the dp/ds is negative in the positive direction and Ut is in the negative dir...