Correlation length by measuring empty space in simulated aggregates
Department of Physics and Astronomy, University of Edinburgh
Edinburgh EH9 3JZ, UK
Accepted: 13 August 2002
We examine the geometry of the spaces between particles in diffusion-limited cluster aggregation, a numerical model of aggregating suspensions. Computing the distribution of distances from each point to the nearest particle, we show that it has a scaled form independent of the concentration ϕ, for both two- (2D) and three-dimensional (3D) model gels at low ϕ. The mean remoteness is proportional to the density-density correlation length of the gel, ξ, allowing a more precise measurement of ξ than by other methods. A simple analytical form for the scaled remoteness distribution is developed, highlighting the geometrical information content of the data. We show that the second moment of the distribution gives a useful estimate of the permeability of porous media.
PACS: 61.43.Hv – Fractals; macroscopic aggregates (including diffusion-limited aggregates) / 82.70.Gg – Gels and sols / 47.55.Mh – Flows through porous media
© EDP Sciences, 2002