A robust algorithm for computational floating body dynamics

Area of Science:

• Computational Fluid Dynamics (CFD)
• Fluid-Structure Interaction
• Numerical Methods

Background:

• Added mass instability is a common issue in CFD simulations involving light bodies interacting with dense fluids.
• Existing methods for coupling rigid body motion and fluid dynamics can be computationally expensive or unstable.

Purpose of the Study:

• To introduce FloatStepper, a novel non-iterative algorithm for stable coupling of rigid body motion and incompressible fluid flow.
• To address and eliminate the added mass instability problem in CFD simulations.

Main Methods:

• Developed a non-iterative algorithm, FloatStepper, for rigid body and incompressible fluid coupling.
• Implemented a probe body motion strategy to decompose forces and torques.
• Integrated the algorithm as an open-source extension for OpenFOAM.

Main Results:

• Demonstrated excellent stability properties across various single-phase and two-phase flow benchmark cases.
• Successfully enabled simulations with massless bodies, showcasing robustness.
• Identified areas for improvement in mesh motion for enhanced flexibility and predictive power.

Conclusions:

• FloatStepper offers a stable and efficient alternative for simulating fluid-body interactions in CFD.
• The open-source implementation facilitates wider adoption and further development.
• Further refinements in mesh motion can expand the algorithm's applicability.