Towards the estimation of wall shear stress in smoothed particle hydrodynamics

Over the past few decades, smoothed particle hydrodynamics (SPH) has emerged as an alternative computational fluid dynamics (CFD) technique, yet the estimation of wall shear stress lacks adequate standardisation. Wall shear stress is a critical metric in numerous applications, and hence, this is the focus of this paper. The present study proposes a novel SPH-based method for estimating wall shear stress using velocity data from the fluid particles adjacent to the wall. Wall shear stress is then calculated at the wall based on the wall shear stress data of the neighbouring fluid particles. For laminar flow, wall shear stress is estimated directly from velocity gradients, while for turbulent flow, the Smagorinsky large eddy simulation (LES) model with eddy viscosity is used. The results obtained from the model are rigorously validated against experimental, simulation and analytical data, confirming its effectiveness across different flow conditions. This validation highlights the reliability of the proposed model for fluid dynamics and bio-fluid mechanics research.