Interplay of inertia and deformability on rheological properties of a suspension of capsules

What is it about?

Suspensions are mixtures of particles and a liquid. In many situations the particles are evenly distributed in the liquid. However, if the suspension is flowing in a pipe, the particles tend to accumulate in certain regions of the pipe. This effect is caused by several mechanisms that can strengthen or weaken each other. In this work we have investigated two particular mechanisms: What happens when the particles are soft? What happens when the flow is moving fast so that inertia becomes important? We have found that both mechanisms show an interesting and unexpected interplay that leads to a hitherto unknown accumulation effect.

Featured Image

Why is it important?

There are, among others, two important factors that affect the behaviour of suspensions: inertial effects (if the Reynolds number is sufficiently large) and particle deformation (if the particles are sufficiently soft). These two effects are usually discussed separately in the literature, but there can be situations where both are important at the same time. The present paper addresses this issue and presents, for the first time, a new effect that is caused by the interplay of inertia and deformation in suspensions.