Blasius Solution for Boundary Layer

[ccrook]

Is the Blasius solution valid for internal flow in an underdeveloped pipe? Can the function for the boundary layer thickness be used to calculate when the boundary layers will meet in the center of the pipe? I don't see how it could be valid since the assumption in its derivation is that pressure is constant across the flat plate, so dP/dx = 0 which is not true for pipe flow. Any thoughts?

 

[Chestermiller]

It is valid for the portion of the entrance region in which the Blasius BL thickness is small compared to the radius of the pipe. In this region, the pipe wall looks like an infinite flat plate.