No Slip Condition: Which is Correct? Explained

[foo9008]

Homework Statement

i was told that

For a given fluid the velocity of fluid in contact with with solid boundary is equal to the velocity of solid boundary in a book . In another book , I was told that the velocity of fluid at the solid boundary is 0 , which is correct ? can someone explain ?

Homework Equations

The Attempt at a Solution

imo , the first one is wrong , the second statement is correct , am i right ? can someone expalin pls?

 

[Nidum]

Taken at face value the first statement allows for the solid boundary to be moving and the second statement assumes that it is not moving . In either case the velocity of the fluid in contact with the solid boundary is zero relative to the boundary .

We really need to see the actual text from the books though to be certain about what is being said about this .