Predictions of microstructure and stress in planar extensional flows of a dense viscous suspension

We consider extensional flows of a dense layer of spheres in a viscous fluid and employ force and torque balances to determine the trajectory of particle pairs that contribute to the stress. In doing this, we use Stokesian dynamics simulations to guide the choice of the near-contacting pairs that follow such a trajectory. We specify the boundary conditions on the representative trajectory, and determine the distribution of particles along it and how the stress depends on the microstructure and strain rate. We test the resulting predictions using the numerical simulations. Also, we show that the relation between the tensors of stress and strain rate involves the second and fourth moments of the particle distribution function.

Automated summary

The study analyzes the extensional flows of a dense layer of spheres in a viscous fluid by using force and torque balances to determine the trajectory of particle pairs. It investigates the relationship between stress, microstructure, and strain rate, and shows that this relation involves the second and fourth moments of the particle distribution function.