(a) Probability distribution function of number of particles in clusters, in the normal region (dashed lines, triangles) and abnormal region (continuous lines, pentagons), for two different densities, 0.2 (pink) and 0.6 (silver). For ϕ = 0.2, entering the abnormal region implies an increase of algebraic exponent ξ, while for ϕ = 0.6 it implies a decrease of ξ. This highlights qualitatively different flowing properties for small and large concentrations. (b) Cluster size as a function of ϕpin for different ϕ. For ϕ < 0.5, the average number of clusters increases gradually with increasing ϕpin, while for ϕ > 0.5 it decreases, showing how in this case interrupting the flow translates into smaller clusters.