Kolmogorov-Sinai Entropy of the Dilute Wet Granular Gas

We present an analytical expression for the Kolmogorov-Sinai entropy of a wet granular gas. The influence of the liquid is modeled by a hysteretic interaction force. For the dilute limit (two-particle collisions only), we find a simple expression accounting for the contribution of both the scattering states and the bound states in arbitrary dimensions. It is shown that the system is significantly more chaotic than a gas of (dry) hard spheres, as reflected by a pronounced increase of the Kolmogorov-Sinai entropy.

Figure 1

The (attractive) force exerted by a liquid capillary bridge between two spheres. Its hysteretic character gives rise to dissipation within the system. Its form is a slight idealization of the experimentally determined force characteristic [18].

Figure 2

The increase of the leading term coefficient $A=(D-1)/2+\Delta A$ in the KSE due to the liquid bridge interaction for two (solid line) and three (dashed line) dimensions.