We simulate a dense athermal suspension of soft particles sheared between hard walls of a prescribed roughness profile, fully accounting for the fluid mechanics of the solvent between the particles and for the solid mechanics of changes in the particle shapes. We, thus, capture the widely observed rheological phenomenon of wall slip. For imposed stresses below the material’s bulk yield stress, we show the slip to be dominated by a thin solvent layer of high shear at the wall. At higher stresses, it is augmented by an additional contribution from the fluidization of the first few layers of particles near the wall. By systematically varying the wall roughness, we quantify a suppression of slip with increasing roughness. We also elucidate the effects of slip on the dynamics of yielding following the imposition of constant shear stress, characterizing the timescales at which bulk yielding arises and at which slip first sets in.

中文翻译：

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软颗粒悬浮液的壁滑和大块屈服

我们模拟了在规定的粗糙度轮廓的硬壁之间剪切的，柔软的颗粒的致密无热悬浮液，充分考虑了颗粒之间溶剂的流体力学以及颗粒形状变化的固体力学。因此，我们捕获了广泛观察到的壁滑流变现象。对于低于材料的整体屈服应力的外加应力，我们显示出滑移受壁上高剪切力的薄溶剂层支配。在较高的应力下，壁附近的前几层颗粒的流化产生了额外的贡献，从而增加了应力。通过系统地改变壁的粗糙度，我们量化了随着粗糙度增加而对滑动的抑制。我们还阐明了在施加恒定剪应力后，滑移对屈服动力学的影响，