Abstract

The Paper presents a mathematical model of unsteady turbulent pipe flow developed using the four-layer distribution of the coefficient of turbulent viscosity. This model is used for determing the hydraulic losses. A detailed discussion deals with the instantaneorrs friction factor for accelerated liquid flow. This coeficient increases with increasing acceleration of liquid flow and decreases with increaiing Reynolds number. It is demonstrated that the instantaneous friction factor considerably differs from the quasi-steady value.