THE PHENOMENON OF DRAG REDUCTION IN FLOWS OF CLAY SUSPENSIONS
粘土悬浮液明渠流的减阻现象

Experiments with clay suspensions flowing over smooth, gravel and stone beds prove that resistance of the flow may be considerably reduced by the suspended sediment if the flow boundary is rough The measured mean velocity of clay suspensions is much higher than the flow of water The friction factor of flows of high clay concentrations over the gravel bed was less than half of the clear water flow on the same hydraulic conditions The high viscosity and yield stress of clay suspensions suppressed the development of turbulent eddies and thus reduced the turbulence intensity The effect of damping turbulence is the cause of the drag reduction For flows over the smooth bed, the effect of damping turbulence is counterbalanced by the effect of increasing viscous resistance, therefore, no drag reduction occurred in this case