论文标题
经过可逆性的过渡的定期剪切悬浮液的流变学
Rheology of periodically sheared suspensions undergoing reversible-irreversible transition
论文作者
论文摘要
在数值上研究了循环剪切下的非胶体悬浮液的流变学。主要发现是剪切应力和第二个正常应力差（$ n_2 $）中的应变振幅（$γ_0$）。具体而言，我们发现粘度降低，增强的内部剪切稀疏，有限$ n_2 $的发作及其频率加倍，所有这些都接近关键应变振幅$γ_c$，以$γ_c\ simc \ sim ϕ^{ - 2} $缩小体积分数$ ϕ $。这些流变学的变化还表示可逆的 - 可逆性转变（RIT），将频道粒子动力学分为可逆的吸收阶段（对于$γ_0<γ_c$）和持续扩散的阶段（对于$γ_0> $γ_0>γ_c$）。我们根据两种流动诱导的机制来解释结果，并通过基础微观结构在RIT的背景下阐明它们的联系，这些微观结构倾向于接近$γ_0=γ_C$。总体而言，我们希望流变学和新兴动态之间的这种对应关系能够在结构组织由体积排除主导的各种环境中保持。
The rheology of non-colloidal suspensions under cyclic shear is studied numerically. The main findings are a strain amplitude ($γ_0$) dependent response in the shear stress and second normal stress difference ($N_2$). Specifically, we find a reduced viscosity, an enhanced intracycle shear thinning, the onset of a finite $N_2$ and its frequency doubling, all near a critical strain amplitude $γ_c$ that scales with the volume fraction $ϕ$ as $γ_c \sim ϕ^{-2}$. These rheological changes also signify a reversible-irreversible transition (RIT), dividing stroboscopic particle dynamics into a reversible absorbing phase (for $γ_0<γ_c$) and a persistently diffusing phase (for $γ_0>γ_c$). We explain the results based on two flow-induced mechanisms and elucidate their connection in the context of RIT through the underlying microstructure, which tends towards hyperuniformity near $γ_0=γ_c$. Overall, we expect this correspondence between rheology and emergent dynamics to hold in a wide range of settings where structural organizations are dominated by volume exclusions.
