A comparative study of transient capillary rise using direct numerical simulations

•Comparison of full continuum solutions using four fundamentally different numerical approaches.•Analysis of different rise regimes providing reference data for liquid rising between plates (available online).•General derivation for the case of critical dampening for the classical rise equation. The rise of liquid in capillaries, or between two parallel plates as the 2D variant thereof, represents a challenging test case for two-phase flow solvers without a full analytic solution. Four different numerical approaches are compared for the rise of liquid, also providing reference data being of high relevance for capillarity-dominated wetting processes. The used methods are an Arbitrary Lagrangian–Eulerian method (OpenFOAM solver interTrackFoam), a geometric Volume of Fluid code (FS3D), an algebraic Volume of Fluid method (OpenFOAM solver interFoam), and a level-set based extended discontinuous Galerkin discretization (BoSSS). While the transient rise height shows excellent agreement between the different implementations, the velocity fields at the interface demonstrate a different level of local accuracy of the available approaches. Reducing the slip length reduces the overall dynamics of the system, thus yielding a qualitative change in the rise behavior – a behavior that is not covered by simplified ODE models. The obtained rise height results are vailable online: http://dx.doi.org/10.25534/tudatalib-173