COUPLED BURGERS EQUATIONS - A MODEL OF POLYDISPERSIVE SEDIMENTATION

TL;DR

This paper investigates the dynamics of polydispersive sedimentation using coupled Burgers equations, comparing theoretical models with experimental data, and exploring effects like thermal fluctuations and polydispersity.

Contribution

It introduces a coupled Burgers equations model for polydispersive sedimentation and compares its predictions with experimental results, highlighting the effects of polydispersity and thermal fluctuations.

Findings

Coupled Burgers equations effectively model sedimentation dynamics.

Polydispersity causes continuous renormalization of particle distribution.

Experimental results support the theoretical predictions.

Abstract

This paper compares theory and experiment for the kinetics of time-dependent sedimentation. We discuss non-interacting suspensions and colloids which may exhibit behavior similar to the one-dimensional motion of compressible gas. The velocity of sedimentation (or creaming) depends upon the volume fraction of the constituting particles and leads to Burgers-like equations for concentration profiles. It is shown that even the bi-dispersive system of two coupled Burgers equations has rich dynamics. The study of polydispersive case reveals a continuous ``renormalization'' of the polydispersity. We compare the Burgers system evolution with the experimental results on mono- and polydispersive sedimentation. The influence of thermal fluctuations is briefly discussed.