Evolution of streamers in sedimentation of fibre suspensions bounded by vertical walls
(English)Manuscript (preprint) (Other academic)
The simulation, based on the Navier-Stokes equations coupled to a transport equation for the PDF of fibres, shows that a series of alternating structures of risers and streamers emerge continuously from the walls until they meet in the middle of the domain. For moderate times, this agrees qualitatively with experimental and theoretical results. Moreover, our simulation in a vessel of infinite height obtained an increasing wavelength evolution due to the congregation of the streamers or risers. In the end, there is constantly only one streamer left, and it drifts randomly to one side of the container until the evolution reaches a steady state. It is also found that the perturbations added to the initial conditions can induce more high density regions which sizes and velocities are strongly linked to the initial perturbations of the number density or the flow field. In addition, the maximum number of streamers increases with Reynolds number, volumefraction and channel width.
particle/fluid flow, suspension, instability
IdentifiersURN: urn:nbn:se:kth:diva-98396OAI: oai:DiVA.org:kth-98396DiVA: diva2:537011
QC 201206252012-06-252012-06-252012-06-25Bibliographically approved