Time-Domain Simulation of Lifting Bodies Acting at or Near the Free Surface with Vortex Particle Wakes

Boundary Element Method (BEM) potential-flow solvers are regularly used in industrial applications due to their quick setup and computational time. In aerodynamics, Vortex Particle Methods (VPM) are widely used with BEM potential-flow solvers for modeling lift. However, they are seldom applied to the ocean environment. This paper discusses the implementation of a VPM into Aegir, an existing time-domain, seakeeping, medium-fidelity, BEM potential-flow solver. The wake in the VPM is modeled using both a small dipole buffer wake sheet as well as vortex particles. It has been observed that this method captures both the details of complex wake patterns behind lift-producing surfaces and the expected lift force, thus improving the accuracy of the solution. Two new contributions presented in this paper include the extension of the VPM from previous source-based methods to a potential formulation and full interaction with free surface waves.