Rapid Free Surface Simulation for Steady-State Hull Resistance with FVM using OpenFOAM

This work describes a novel method to calculate resistance force at steady forward motion with free-surface simulation using the viscous turbulent flow model in Volume-Of-Fluid (VOF) formulation. Assuming quasi steady-state solution, equations for fluid flow and free-surface motion are decoupled due to separation of time-scales. It is thus possible to increase the time-step size by about 3 orders of magnitude and preserve numerical stability, which gives a substantial increase in computational efficiency. The method has been implemented and tested in FOAM-Extend, a fork of the OpenFOAM software. KCS and DTMB hull geometries are simulated with the novel method and results are compared with experimental data. The accuracy is equal to simulations with a conventional transient approach. Performance and parallel scalability are assessed. The results show that the novel method delivers substantially increased computational efficiency without sacrifice of accuracy.