It is argued that ejections of wall fluid in the bursting process disturb the flow beyond the wall layer and result in the emergence of two new layers in the flow field: the law of the wake and log-law layers. The wall layer represents the extent of penetration of viscous momentum into the main flow and remains constant once it has reached a critical value at the end of the laminar regime. The identification of the three flow regimes: laminar, transition and fully turbulent is conveniently achieved by monitoring the emergence of these three layers
Categories: physics.flu-dyn