Creeping flow over spherical permeable aggregates

摘要: Abstract Creeping flow past an isolated, spherical and permeable aggregate has been studied, adopting the Stokes equation to model fluid external Brinkman for internal flow. The is assumed have a fractal structure with radially varying solid fraction permeability. results summarised in terms of three parameters: drag coefficient Ω , collection efficiency η settling factor Z. Such quantities depend only on dimensionless size, R/a, dimension factor. When larger than 2, it not necessary consider its non-homogeneous radial change local properties. Accurate can be obtained by modelling particle as homogeneous, void constant fraction, equal surface value, evaluating according analytical expressions valid aggregates uniform