Dynamics of prolate ellipsoidal particles in a turbulent channel flow

• Published in: Physics of fluids (1994) Vol. 20; no. 9; pp. 093302 - 093302-14
• Main Authors: Mortensen, P. H., Andersson, H. I., Gillissen, J. J. J., Boersma, B. J.
• Format: Journal Article
• Language: English
• Published: Melville, NY American Institute of Physics 01.09.2008
• Subjects: Exact sciences and technology; Flows in ducts, channels, nozzles, and conduits; Fluid dynamics; Fundamental areas of phenomenology (including applications); Multiphase and particle-laden flows; Nonhomogeneous flows; Physics; Turbulent flow; Pipe flow; Two-phase flow; Digital simulation; Modelling; Particle suspension; Aspect ratio; Ellipsoid
• ISSN: 1070-6631; 1089-7666
• DOI: 10.1063/1.2975209

The dynamical behavior of tiny elongated particles in a directly simulated turbulent flow field is investigated. The ellipsoidal particles are affected both by inertia and hydrodynamic forces and torques. The time evolution of the particle orientation and translational and rotational motions in a statistically steady channel flow is obtained for six different particle classes. The focus is on the influence of particle aspect ratio λ and the particle response time on the particle dynamics, i.e., distribution, orientation, translation, and rotation. Both ellipsoidal and spherical particles tend to accumulate in the viscous sublayer and preferentially concentrate in regions of low-speed fluid velocity. The translational motion is practically unaffected by the aspect ratio, whereas both mean and fluctuating spin components depend crucially on λ . The ellipsoids tend to align themselves with the mean flow direction and this tendency becomes more pronounced in the wall proximity when the lateral tilting of the elongated particles is suppressed.