Abstract
Self-diffusion coefficients were determined experimentally for lateral dispersion of spherical and disk-like particles in linear shear flow of a slurry at very low Reynolds number. Using a concentric-cylinder Couette apparatus, recurrent observations were made of the lateral position of a particular radioactively labelled particle. The self-diffusion coefficient D was calculated by means of random-walk theory, using the ergodic hypothesis. Owing to great experimental difficulties, the calculated values of D are not of high accuracy, but are correct to within a factor of two. In the range 0 < ϕ < 0·2, D/a2ω increases from zero linearly with ϕ up to D/a2ω ≈ 0.02 (where ϕ = volumetric concentration of particles, a = particle radius, ω = mean shear rate of suspending fluid). In the range 0.2 < ϕ < 0.5, the trend of D/a2ω is not clear because of experimental scatter, but in this range D/a2ω ≈ 0·025 to within a factor of two. Within the experimental accuracy, spheres and disks have the same value of D/a2ω.
Publisher
Cambridge University Press (CUP)
Subject
Mechanical Engineering,Mechanics of Materials,Condensed Matter Physics
Reference43 articles.
1. Smith, A. M. O. & Hess, J. L. 1967 Calculation of potential flow about arbitrary bodies.Prog. Aero. Sci. 8,1–138.
2. Martensen, E. 1959 Die Berechnung der Druckverteilung an dicken Gitterprofilen mit Hilfe der Fredholmschen Integralgleichungen zweiter Art.Arch. Rat. Mech. Anal. 3,235–270.
3. Lotz, I. 1931 Zur Berechnung der Potentialströmung um quergestellte Luftschiffkörper.Ing.-Arch. 2,507–527.
4. Körner, H. 1972 Berechnung der potentialtheoretischen Strömung um Flügel-Rumpf-Kombinationen und Vergleich mit Messungen.Z. Flugwiss. 20,351–368.
5. Hess, J. L. Survey of first-order panel methods.
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