Relaxation and flow in linearly sheared two-dimensional foams

We probe the relation between rheology and shear-induced relaxation in experiments on two-dimensional foams at steady shear. The characteristic relaxation time t r , which we extract from the non-affine part of the bubble displacements, scales non-linearly with the local strain rate . In particular, the relative strength of the non-affine part grows when —hence the foam flow is not quasistatic down to the lowest experimentally accessible shear rate. Furthermore, we establish a direct connection between the relaxation time scaling and the macroscopic rheology.