ReFRESCO is a viscous-flow CFD code that solves multiphase unsteady incompressible flows using the RANS equations. ReFRESCO is an acronym for Reliable&Fast Rans Equations (solver for) Ships, Cavitation (and) Offshore. ReFRESCO resembles in several regards a general commercial CFD code, but it is optimized, verified and validated exclusively for maritime applications. ReFRESCO is currently being actively developed, verified and validated at MARIN (in the Netherlands) in collaboration with IST (in Portugal), USP-TPN (University of Sao Paulo, Brasil), TUDelft (Technical University of Delft, the Netherlands), UoS (University of Southampton, UK), and recently at UTwente (Technical University of Twente, the Netherlands) and Chalmers (Chalmers University of Technology, Sweden).

Propeller in open water
Computational approach
ReFRESCO solves the multi-phase unsteady incompressible RANS (Reynolds-averaged Navier-Stokes) equations, complemented with turbulence models and volume-fraction transport equations for each phase. The equations are discretised using a finite-volume method with cell-centered variables in physical space. The implementation is face-based, which permits grids with elements with an arbitrary number of faces or locally refined grids with hanging nodes. This increases the applicability of the code to almost any geometry. The pressure/velocity coupling is achieved using a SIMPLE segregated method or a Krylov-based SIMPLE(r,c) coupled approach. The code has several state-of-the-art CFD features such as moving, sliding, deforming and adaptive grids, new turbulence model approaches such as DES/SAS/PANS/LES and several cavitation models (for more details on the current status of these check ReFRESCO community.

ReFRESCO runs on Linux workstations and HPC clusters. The code is parallelised using MPI and subdomain decomposition, and has been tested to have linear speed-up up to 1900 cores. In order to guarantee the quality and easy maintenance of a complex code such as ReFRESCO, automatic testing, verification and validation procedures are used, as well as modern version control systems.

Use of the program
ReFRESCO is a general and flexible tool, and it aims at dealing with all typical hydrodynamic problems relevant to MARIN. It has already been used in powering, propulsion, seakeeping, manoeuvring, offshore, and renewable-energy studies.

Some recent research done using ReFRESCO:

  • Scale effects for ship and offshore flows
  • Analysis of complex propulsion (ship+propeller+rudder) systems
  • Analysis of energy-saving devices
  • Manoeuvring, current and wind forces on ships and offshore structures
  • Thruster-hull and thruster-thruster interaction
  • Shallow water effects on manoeuvring
  • Analysis of the flow around submarines
  • Analysis of current and floating wind turbines
See ReFRESCO publications for examples of applications for which both verification and validation studies have been performed. See ReFRESCO community for more detailed info on the code, its usage and to have a detailed impression on ReFRESCO. A leaflet on ReFRESCO can be found here.

For more information about ReFRESCO, contact our R&D Department at or

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