Before revision: Accurate simulation of fluid flow in the presence of complex geometries with mesh-free  methods requires that the geometry surfaces be captured accurately with particles. The traditional ways to do this with particlesdo not result in an accurate representation of the geometry surfaces.
After revision: Accurate simulation of fluid flow in the presence of complex geometries with mesh-free methods requires that the geometry surfaces be captured accurately . Methods like weakly-compressible and incompressible smoothed particle hydrodynamics (SPH) perform better when the particle distribution is uniform. Moreover, SPH schemes typically require the mass or volume to be constant for all particles. For a uniform density, this necessitates a good initial particle distribution.