Minimizing Numerical Ventilation in Computational Fluid Dynamics Simulations of High-Speed Planning Hulls

Abstract

Numerical ventilation (NV) is a well-known problem that occurs when the volume of fluid method is used to model vessels with a bow that creates an acute entrance angle with the free surface, as is typical for both planing hulls and yachts. Numerical ventilation may be considered one of the main sources of error in numerical simulations of planning hulls and as such warrants an in-depth analysis. This paper sets out to bring together the available work, as well as performing its own investigation into the problem to develop a better understanding of numerical ventilation and present alternate solutions. Additionally, the success and impact of different approaches are presented in an attempt to help other researchers avoid and correct for numerical ventilation. Interface smearing caused by the simulation being unable to track the free surface is identified as the main source of numerical ventilation. This originates from the interface between the volume mesh and the prism layer mesh. This study investigates this interface, presenting a novel solution to prism layer meshing that was found to minimize numerical ventilation. Through the implementation of a modified high-resolution interface capture (HRIC) scheme and the correct mesh refinements, it is possible to minimize the impact of numerical ventilation to a level that will not affect the results of a simulation and is acceptable for engineering applications.