Analysis of the Velocity Boundary Layer in Pipeline Flow

The equation of velocity boundary layer in pipeline flow is deduced out by adopting the integral method of momentum.The analysis result of velocity distribution and boundary layer thickness is put forward in the boundary layer and cored region for laminar and turbulent flow of pipeline.The result is compared with Von KARMAN's momentum equation.The calculation expression of length at entry of velocity boundary layer about laminar and turbulent flow is obtained.The value is smaller than the existing result in which the formula is given in the teaching material.It is proved that the development of velocity boundary layer is far quicker than the temperature boundary layer.Hence,the assumption is reasonable that velocity boundary layer is fully developed when we study the temperature boundary layer in pipeline flow.