Steady Flow in Tubes

Abstract

When flow enters a tube, the no-slip boundary condition on the tube wall arrests fluid elements in contact with the wall while elements along the axis of the tube charge ahead, less influenced by that condition. Because viscosity of the fluid does not allow a step change in velocity to occur anywhere in the flow field, a smooth velocity profile develops to join the faster moving fluid along the axis of the tube with the stationary fluid at the tube wall.