摘要：Curve/surface smoothing is a problem that appears in different fields, such as computer graphics and computational fluid mechanics. In fluid flow simulation with free surface, particularly when the Reynolds number is high, small undulations may appear at the free surface due to variations in the velocity field from cell to cell. These undulations are frequently much smaller than a cell size and a numerical implementation that acts at cell level cannot take into account these sub-cell undulations, being necessary suppress them. There are several approaches that can be used to smooth these unphysical undulations, such as Gaussian filter. However, in fluid flow simulations it is important that the smoothing process keeps the mass (or volume) unchanged. In this work we present a smoothing technique that suppresses undulations while still conserving the mass. The approach consists in computing a local volume which is preserved during the smoothing process. The results of applying such technique in planar, axisymmetric, and three-dimensional free-surface flows are presented and discussed.
