A Lagrangian free-stream boundary condition for weakly compressible smoothed particle hydrodynamics

This paper proposes the first free-stream boundary condition in a purely Lagrangian framework for weakly-compressible smoothed particle hydrodynamics (WCSPH). The is implemented based on several numerical techniques, including spatio-temporal method and an ensuring technique surface identification, far-field corrections of density velocity near boundary, improved in- outlet conditions which guarantee smooth inflow profile free outflow particles without issue truncated kernel. accuracy effectiveness have been validated by reference solutions flow past flat plate circular cylinder, respectively. has also tested with more complex flows to demonstrate its applicability, such as fluid-structure interaction (FSI) 3D sphere.