Shear-Induced Lift Force on Micro-Fiber Deposition in Low Reynolds Number Flows

Abstract

Abstract Shear-induced lift lateral migration significantly affects fiber deposition in wall-bounded flows. In the absence of active physical transport mechanisms, the contribution of the shear-induced lift could become the driving deposition force. Due to technical difficulties, investigation into this phenomenon has been limited, and its implication on particle deposition has not been fully understood. This study explored the effect of shear-induced lift and rotation on micro-fiber transport and deposition in low Reynolds number flows. Transport and deposition of non-neutrally buoyant ellipsoidal fibers in Poiseuille flow in horizontal and vertical ducts are examined numerically, and various lateral migration scenarios are investigated. It was found that, in the absence of sideway gravity, shear-induced lift and rotation cause the fibers to drift across the flow streamlines in a vertical channel. This lateral movement is the driving force for fiber deposition in downward flows or moves. In contrast, the particles move toward the channel center in an upward flow configuration. The lateral migration velocity in the vertical channel correlates positively with fiber length and shear rate. The lateral migration in a horizontal duct is comparatively small, where the sideway gravity is dominant. The current study identified the flow scenarios where the lateral migration driven by the shear-induced lift is the dominant contributing factor for deposition and, therefore, should not be neglected.