FLOW-3D Extension: TruVOF

Although generally very accurate for
most free-surface flows, the standard
VOF option had some deficiencies
when tracking diagonally-moving fluids

From its inception, FLOW-3D has excelled at simulation free surface problems due to the accuracy of its implementation of the Volume-of-Fluid (VOF) method for tracking sharp interfaces and applying boundary conditions. With Version 8.2, Flow Science is extending its quality another notch. A new VOF advection method, which we're calling TruVOF, has been implemented that is based on a three-dimensional reconstruction of moving volume elements.

The standard VOF method for tracking interfaces uses operator splitting to compute material fluxes in three coordinate directions. This approach creates a possibility of over-filling or over-emptying computational cells. Furthermore, with the standard method it is not possible to directly move material diagonally into neighboring corner cells. The new approach alleviates these deficiencies of the old algorithm. Fluid interfaces are reconstructed in three-dimensions using a piecewise linear representation, where the interface is assumed to be planar in each control volume. The fluid volume bounded by the interface surface and cell faces is then moved according to the local element velocity in a Lagrangian manner. Finally, the advected volume is overlaid back onto the Eulerian grid to obtain the new values of the fraction-of-fluid function.

Extending the boundaries of accurate simulation is another way in which the value of FLOW-3D continues to increase.