On the application of overset meshing to numerical studies of roll damping of hulls in complex scenarios
Kemeng Xi, Ian Milne, Scott Draper, Lifen Chen
Abstract
The application of computational fluid dynamics (CFD) and overset meshing, to predict the roll response of ships is of significant interest to ocean engineering. Despite its growing popularity, it remains essential to validate the efficacy of computations using overset meshing for modelling strong vortex flows, particularly in complex geometric scenarios involving relative motion and narrow gaps, and for deriving roll damping coefficients. This study presents a new series of results in which the solvers and overset meshing methods in the open-source CFD code, OpenFOAM, were applied to compute the vortex flow from sharp edges and the roll damping of hulls, including the particularly complex scenario of a hull rolling next to a solid vertical wall. It has been demonstrated that the methods can effectively model the intricate flow physics associated with flow separation, including the shedding of primary and secondary vortices, and reliably estimate damping coefficients. Further, the study provides suitable numerical configurations for overset mesh applications and new insights to explain the discrepancies between experimental and numerical results. These new results not only contribute to the understanding of wave-induced roll response but also reinforce the value of the overset mesh technique for the prediction of related problems in fluid mechanics.