EFFECT OF CONCENTRATION ON SETTLING VELOCITY OF SEDIMENT PARTICLES

The drag coefficient for dispersed particles settling in a fluid is re lated to the particle Reynolds number with the same function as that u sed for a single particle falling in a clear fluid, after taking into account the effects of concentration both on the effective density of particles and on the viscosity of fluid-sediment mixture. A new method is developed for evaluating the settling velocity of natural sediment particles dispersed in a fluid; it agrees well with the available exp erimental data. The differences among various empirical expressions ar e illustrated using the present relationship.