Effect of nonstationarity in the motion of an open fluid flow

A way of taking the effects of unsteady motion into consideration in boundary layer theory has been found recently [1]. In the meantime, in hydraulics ever-increasing interest is being shown in the application of the ideas and methods of boundary layer theory to the study channel flows. We have attempted here to apply this hydrodynamic approach in deriving the law of resistance for turbulent unsteady flows in open channels.