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Session: Multiphase and non-Newtonian flows 2
Session starts: Thursday 27 August, 10:30
Presentation starts: 11:30
Room: Room D

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Agathe Chouippe (Institute for Hydromechanics, KIT, Germany)
Todor Doychev (Institute for Hydromechanics, KIT, Germany)
Markus Uhlmann (Institute for Hydromechanics, KIT, Germany)

Abstract:
We have simulated the gravity-induced settling of finite-size particles in a turbulent background flow which is forced in a statistically-stationary fashion. The simulations are accurately resolving the solid-fluid interface with the aid of an immersed boundary technique [1]. The parameters of the simulation are (apart from background turbulence) identical to those of reference [2], where particle clustering was observed at a Galileo number of 178 and a solid volume fraction of 0.005. In the present case, it is found that a relative turbulence intensity of 0.24 leads to the disappearance of the clusters; as a consequence, the increase in average particle settling velocity found in [2] also vanishes. [1] M. Uhlmann. An immersed boundary method with direct forcing for the simulation of particulate flows. J. Comput. Phys., 209(2):448–476, 2005. [2] M. Uhlmann and T. Doychev. Sedimentation of a dilute suspension of rigid spheres at intermediate Galileo numbers: the effect of clustering upon the particle motion. J. Fluid Mech., 752:310–348, 2014.