Settling velocity impermeable

The case of impermeable spherical aggregates has been analyzed by Johnson el al. (Johnson et al., 1996). In this work, the settling velocity of aggregates in liquids using Stoke s law has been studied and a modified Stoke s law has been introduced. The difference from the classical Stoke s law is that the density difference is expressed in terms of the aggregate density. 

Numerous attempts have been made to develop mathematical models [99-107] to describe particle settling. Settling velocities of impermeable spheres are generally derived by balancing gravity F, buoyant / b, and drag forces. By introducing the... 

Calculation of the terminal velocity of a porous sphere is useful and important in applications in water treatment where settling velocities of a floe or an aggregate are estimated. It is also important in estimation of terminal velocities of clusters in fluidized bed applications. The terminal velocity of a porous sphere can be quite different from that of an impermeable sphere. Theoretical studies of settling velocity of porous spheres were conducted by Sutherland and Tan (1970), Ooms et al. (1970), Neale et al. (1973), Epstein and Neale (1974), and Matsumoto and Suganuma (1977). The terminal velocity of porous spheres was also experimentally measured by Masliyah and Polikar (1980). In the limiting case of a very low Reynolds number, Neale et al. (1973) arrived at the following equation for the ratio of the resistance experienced by a porous (or permeable) sphere to an equivalent impermeable sphere. An equivalent impermeable sphere is defined to be a sphere having the same diameter and bulk density of the permeable sphere. 

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