Wall slip and bulk flow heterogeneity in a sludge under shear

• DOI: 10.1007/s00397-024-01479-3
• Publication Date: 2025-01-14T00:59:39Z
• Authors: Sébastien Castel; Arnaud Poulesquen; Sébastien Manneville
• Keywords: Rheometry

Abstract We investigate the shear flow of a sludge mimicking slurries produced by nuclear industry and constituted dispersion non-Brownian particles into an attractive colloidal at total solid volume fraction about 10 %. Combining rheometry ultrasound imaging, we show that, upon decreasing rate, transitions from homogeneous profile in bulk to fully arrested plug-like state with wall slip, through oscillatory regime where strong fluctuations slip velocity propagate along vorticity direction. When stress is imposed close yield stress, rate presents large, quasi-periodic peaks, associated propagation local stick-and-slip events Such complex dynamics, reminiscent similar phenomena reported much denser suspensions, highlight importance characterization understand rheology.