Author(s): Kiyosi Kawanisi; Peter Nielsen; Mahmoud F. Maghrebi
Linked Author(s): Kiyoshi Kawanishi
Keywords: Settling velocity; Stokes number; Turbulence; Vortex trapping; Fast tracking
Abstract: The motion of light and heavy particles is investigated in a cellular flow in order to examine the reducing and enhancing effects of turbulent eddies on the settling or rise of suspended particles. The numerical results show that even light particles get onto the “fast tracks” and experience enhanced rise. Two significant mechanisms: “fast tracking” and “vortex trapping” exist together in most cases. It seems that the changes of settling/rise velocity of suspended particles are determined by the relative turbulence strength and the Stokes number. The enhanced settling/rise of suspended particles are found with large relative turbulence strength and large Stokes number. The parameter ranges, within which enhanced settling/rise occur, are deduced from the numerical results. Moreover, it is found that the “fast tracking” and “vortex trapping” bring about the reduced Lagrangian velocity variances of suspended particles.
Year: 2007