标题： 污泥在剪切作用下的滑移和体流动不均匀性 显示英文标题

标题： Wall slip and bulk flow heterogeneity in a sludge under shear

摘要： 我们研究了模拟核工业产生的泥浆的剪切流，这些泥浆由非布朗颗粒在总固体体积分数约为10%的吸引力胶体分散体系中的分散组成。结合流变测量和超声波流成像，我们表明，随着剪切速率的降低，流动从主体中的均匀剪切剖面过渡到完全停滞的塞状状态，并伴有整体壁滑移，通过一个振荡区域，在该区域中滑移速度的强烈波动沿涡度方向传播。当剪切应力接近屈服应力时，剪切速率表现出大而准周期性的峰值，这与沿涡度方向局部的粘滑事件传播有关。这种复杂的动力学，类似于在更密集的悬浮液中报道的类似现象，突显了局部流动表征对于全面理解污泥流变学的重要性。 显示英文摘要

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