Transport and detachment of colloidal particles with irregular shapes occur in geology, environmental, and water-resource engineering. We investigated the effect of shape and aspect ratio on the detachment of non-spherical microparticles attached to a plane substrate, in Couette linear shear flow, under favourable conditions. The detachment conditions were determined by the mechanical equilibrium of drag, lift, gravity and adhesion forces acting on the particle. Drag and lift were evaluated using Computational Fluid Dynamics (CFD), introducing the shape-dependent corrections into traditional formulae for spherical particles. The adhesive particle–surface force is determined by the Surface Element Integration (SEI) method, which also corrects the classical DLVO expression. The forces exerted on spheroids and cylinders can significantly differ from spheres and their detachment exhibit non-monotonic dependencies with aspect ratio. Direct visualisation experiments were performed by piecewise-constant change of flow velocity and the observed detachment were in good agreement with the mechanical-equilibrium based predictions.

具有不规则形状的胶体颗粒的运输和分离发生在地质，环境和水资源工程中。我们研究了形状和长宽比对在良好条件下在Couette线性剪切流中附着于平面基板的非球形微粒的分离的影响。分离条件由作用在颗粒上的阻力，升力，重力和粘附力的机械平衡确定。使用计算流体动力学（CFD）评估了阻力和升力，并将形状相关的校正引入了球形颗粒的传统公式中。胶粘剂颗粒的表面力是通过表面元素积分（SEI）方法确定的，该方法也可以校正经典的DLVO表达式。施加到球体和圆柱体上的力可能与球体显着不同，并且它们的分离显示出与宽高比无关的单调依赖性。通过逐段恒定的流速变化进行直接可视化实验，观察到的脱离与基于机械平衡的预测非常吻合。