Estimating the viscoelastic moduli of a complex fluid from observation of Brownian motion

摘要

A procedure is proposed to estimate the viscoelastic properties of a complex fluid from the behavior of the velocity autocorrelation function of a suspended Brownian particle in a limited range of time. The procedure is tested for a model complex fluid with given frequency-dependent shear viscosity. It turns out that the procedure can provide a rather accurate prediction of the viscoelastic properties of the fluid on the basis of experimental data on the velocity autocorrelation function of the Brownian particle in the range of time where it turns negative.