Finding the constant in the velocity function?

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The discussion centers on finding the constant 'a' in a velocity function, with confusion about its relation to wall equations. Participants note that the constant can be derived from wall equations, but question how these equations connect to the velocity function, which could theoretically be arbitrary. Clarification is provided on the "no slip at the walls" condition, indicating that fluid velocity is zero at the walls. This condition reinforces the relationship between the velocity function and the wall equations. Understanding these concepts is crucial for solving the problem effectively.
theBEAST
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Homework Statement


I am confused about how to get the constant a in this equation.
A9UENXX.png


The Attempt at a Solution


Apparently you can get the constant a from the wall equations. However I don't see how the wall equations are related to the velocity function. The velocity function could have been ANY arbitrary function right? So how can it be related to something else?
 
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theBEAST said:

Homework Statement


I am confused about how to get the constant a in this equation.
A9UENXX.png


The Attempt at a Solution


Apparently you can get the constant a from the wall equations. However I don't see how the wall equations are related to the velocity function. The velocity function could have been ANY arbitrary function right? So how can it be related to something else?
What does "no slip at the walls" mean?

Does it mean that the water flow right along each wall is zero?
 
theBEAST said:

Homework Statement


I am confused about how to get the constant a in this equation.
A9UENXX.png


The Attempt at a Solution


Apparently you can get the constant a from the wall equations. However I don't see how the wall equations are related to the velocity function. The velocity function could have been ANY arbitrary function right? So how can it be related to something else?

No slip at the walls means that u = 0 when (y,z) lies on either wall. We also have u = 0 when y = a + |z|.
 
Ray Vickson said:
No slip at the walls means that u = 0 when (y,z) lies on either wall. We also have u = 0 when y = a + |z|.

Wow cool, thank you :)
 
Question: A clock's minute hand has length 4 and its hour hand has length 3. What is the distance between the tips at the moment when it is increasing most rapidly?(Putnam Exam Question) Answer: Making assumption that both the hands moves at constant angular velocities, the answer is ## \sqrt{7} .## But don't you think this assumption is somewhat doubtful and wrong?

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