Tohoku University, Aramaki-Aoba 6-6-01, Sendai, 980-8579, Japan
In this study, attempts to suppress numerical viscosity in incompressible smoothed particle hydrodynamics (SPH) computations are reported. Two-dimensional computations are performed for inviscid and viscous ﬂows to evaluate the effects of numerical viscosity suppression. The ﬁrst approach is to reduce numerical viscosity at the wall by considering only the wall-normal components of the forces between ﬂuid particles and wall particles. The second approach is to reduce numerical viscosity within the ﬂow ﬁeld by employing elliptic kernel functions whose major axes are aligned with the local mean ﬂow direction. It is found that special treatment of the wall radically reduces the numerical wall friction. Using an elliptic kernel function is found to work reasonably well in reducing numerical viscosity.