Cellwise conservative unsplit advection for the volume of fluid method

• Published in: Journal of computational physics Vol. 283; pp. 582 - 608
• Main Authors: Comminal, Raphaël, Spangenberg, Jon, Hattel, Jesper Henri
• Format: Journal Article
• Language: English
• Published: Elsevier Inc 15.02.2015
• Subjects: Advection; Cellwise approach; Computational fluid dynamics; Donating region; Fluid flow; Fluids; Intersections; Liquids; Mathematical analysis; Pre-image backward tracing; Unsplit advection scheme; Volume conservation; Volume fraction; Volume of fluid; Cellwise approach; Pre-image backward tracing; Volume conservation; Unsplit advection scheme; Donating region; Volume of fluid
• ISSN: 0021-9991; 1090-2716
• DOI: 10.1016/j.jcp.2014.12.003

We present a cellwise conservative unsplit (CCU) advection scheme for the volume of fluid method (VOF) in 2D. Contrary to other schemes based on explicit calculations of the flux balances, the CCU advection adopts a cellwise approach where the pre-images of the control volumes are traced backwards through the flow map. The donating regions of the fluxes are calculated via the streaklines of the grid intersections, represented as polygonal chains whose vertices are determined by backward tracing of particles injected in the flow at different times. High order accuracy is obtained from the fourth-order Runge–Kutta method, where intermediate velocities along pathlines are determined with quadratic temporal and bicubic spatial interpolations. The volumes of the donating regions are corrected in order to fulfill the discrete continuity of incompressible flows. Consequently, the calculation produces non-overlapping donating regions and pre-images with conforming edges to their neighbors, resulting in the conservativeness and the boundedness (liquid volume fraction inside the interval [0,1]) of the CCU advection scheme. Finally, the update of the liquid volume fractions is computed from the intersections of the pre-image polygons with the reconstructed interfaces. The CCU scheme is tested on several benchmark tests for the VOF advection, together with the standard piecewise linear interface calculation (PLIC). The geometrical errors of the CCU compare favorably with other unsplit VOF-PLIC schemes. Finally, potential improvements of the VOF method with the use of more precise interface representation techniques and the future extension of the CCU scheme to 3D are discussed. •Cellwise VOF-update through backward tracing of the cell's pre-image.•Accuracy enhanced via bicubic spatial interpolation and polygonal chain streakline.•The CCU advection scheme is fully conservative and bounded.•No limitation on the Courant number.•Geometrical errors dominated by PLIC interface representation errors.