We measure the velocity of the flow at a point directly touching a flat plate in a laminar flow (see image). Depiction of the point directly touching the surface.

Question

What will be the measured velocity of the flow (in m/s)?
Note that the flow inside the boundary layer is still laminar

Answer 1

In a laminar flow over a flat plate, the velocity of the fluid at the very surface of the plate (the boundary) is zero due to the no-slip condition. This principle states that the fluid in immediate contact with a solid surface will have zero velocity relative to that surface.

Therefore, if you measure the velocity of the flow at the point directly touching the flat plate, the measured velocity will be:

0 m/s.

This applies regardless of the overall flow velocity outside the boundary layer.