A robust algorithm for computational floating body dynamics

J. Roenby*, S. Aliyar, H. Bredmose

*Corresponding author

Publikation: Bidrag til tidsskriftTidsskriftartikelForskningpeer review


We present a non-iterative algorithm, FloatStepper, for coupling the motion of a rigid body and an incompressible fluid in computational fluid dynamics (CFD) simulations. The purpose of the algorithm is to remove the so-called added mass instability problem, which may arise when a light, floating body interacts with a heavy fluid. The idea underlying the presented coupling method is to precede every computational time step by a series of prescribed probe body motions in which the fluid response is determined, thus revealing the decomposition of the net force and torque into two components: (i) an added mass contribution proportional to the instantaneous body acceleration and (ii) all other forces and torques. The algorithm is implemented and released as an open-source extension module to the widely used CFD toolbox, OpenFOAM, as an alternative to the existing body motion solvers. The accuracy of the algorithm is investigated with several single-phase and two-phase flow benchmark cases. The benchmarks demonstrate excellent stability properties, allowing simulations even with massless bodies. They also highlight aspects of the implementation, such as the mesh motion method, where it can be improved to further enhance the flexibility and predictive capabilities of the code.

TidsskriftRoyal Society Open Science
Udgave nummer4
Antal sider25
StatusUdgivet - 3 apr. 2024

Bibliografisk note

Funding Information:
The work presented here was funded by the FloatStep Grand Solution project (8055-00075B) from Innovation Fund Denmark to Stromning Aps and Technical University of Denmark. J.R. also acknowledges partial funding from the DFF Sapere Aude Research Leader grant, InterFlow, to Roskilde University by Independent Research Fund Denmark (9063-00018B). Acknowledgement


  • added mass
  • computational fluid dynamics
  • floating body dynamics
  • FloatStepper
  • numerical methods
  • OpenFOAM

Citer dette