HELYX-Hydro is an extension module for HELYX featuring a specialised two-phase VOF type solver originally developed by the Council for Scientific and Industrial Research (CSIR) in South Africa. This solver add-on package is ideal for modeling violent tank sloshing, cryogenic sloshing, microgravity and microfluidics, liquid transport (marine and air) and coastal structures.

Why HELYX-Hydro?

HELYX-Hydro relies on the 2nd order Crank-Nicolson, HiRAC interface capturing scheme to provide a highly accurate representation of the free-surface between immiscible fluid phases. Together with an improved pressure-interpolation scheme, this method has proven to reduce both spurious dissipation and parasitic currents on non-orthogonal grids when compared to the standard multi-dimensional limiter for explicit solution (MULES) algorithm.

HELYX-Hydro also features advanced thermal capabilities, including heat-mass transfer and liquid film evaporation between discrete liquid and gas phases.

Other key features provided with HELYX-Hydro include, but are not limited to:

Efficient handling of heterogeneous porous fields.
Accounting for gas compressibility in the low-Mach number regime.
Improved coupling algorithm for FSI problems.
Effective handling of multiple regions in the mesh.

HELYX-Hydro experimental validation for violent tank sloshing (courtesy of the CSIR).


HELYX-Hydro thermal capabilities. Droplet on heated plate: Leidenfrost phenomenon (test case created by C. Kunkelmann & S. Batzdorf, TTD-TUD).


Oxtoby O. and Heyns J.A., "A solver for free-surface flow in heterogeneous porous media", OFW9 2014.

Heyns J.A., Oxtoby O. and Suliman R., "Modelling dynamic liquid-gas systems: Extensions to the volume-of-fluid solver", OFW8 2013.

Heyns J.A., Oxtoby O. and Suliman R., "A finite-volume solver for two-fluid flow in heterogeneous porous media based on OpenFOAM". OSCFD 2013.

Want to Buy?

The solvers in HELYX-Hydro are released under the GNU General Public License for the benefit of the end-user. For further information about HELYX-Hydro features, availability and prices, please contact us today or speak to one of our local sales representatives.