Efficient implementation of THINC scheme: A simple and practical smoothed VOF algorithm

In this paper, we improve the multi-dimensional THINC (tangent of hyperbola for interface capturing) scheme [F. Xiao, Y. Honma, T. Kono, A simple algebraic interface capturing scheme using hyperbolic tangent function, Int. J. Numer. Meth. Fluid. 48 (2005) 1023]. The THINC scheme is a VOF (volume of fluid) type method. In the original THINC scheme, one-dimensional THINC scheme was straightforwardly used for multi-dimensional cases. In this paper, we propose the WLIC (weighed line interface calculation) method to extend the THINC scheme to multi-dimension. In the WLIC method, the interface is reconstructed by taking an average of line interfaces along x, y and z coordinates with the weights calculated from surface normal. The WLIC method can extend the THINC scheme to multi-dimension while maintaining simplicity of implementation and achieve a higher accuracy than the original THINC scheme. The WLIC method can readily extend the THINC scheme to three-dimension.