Hydrodynamic Forces and Flow Characteristics Around a Rigid Helical-Shaped Metallic Chip in Shear Flow Near a Plane Wall

Abstract

Abstract. This study investigates the hydrodynamic behavior of a rigid, helical-shaped metallic chip placed near a planar wall in a linear shear flow using numerical methods. The flow characteristics are analyzed across a range of Reynolds numbers (2≤Re≤100) and varying helical pitch values (0.5≤ϕ≤1.5). The computational domain is discretized using a polyhedral mesh with a refined near-wall region to capture high gradients in flow. A mesh independence study, followed by a validation case ensures the accuracy of results. The drag, lift, and moment coefficients of the helical chip are evaluated as functions of pitch and wall proximity. The results indicate that pitch significantly influences both pressure and viscous forces. With higher pitch values, greater flow penetration, and stronger vortex structures are noticed. A strong dependency of drag and lift forces on Reynolds number was observed, and empirical correlations were proposed in this work for predicting force coefficients. It is found that the lift force increases with the increase in Reynolds number and pitch. Flow visualization reveals distinct recirculation zones and vortex formations, highlighting the effect of ground clearance on flow separation. This study provides insights into the hydrodynamic behavior of helical chips in shear flows, relevant to applications in particle transport, food industry, and bio-inspired propulsion systems. The observations from the study can be effectively used to design microfluidic devices that sort particles based on their chirality or geometry.