Some Results from a New Time-Domain Bilge Keel Force Model
A new non-linear, time domain bilge keel force model was recently developed for inclusion in the new time-domain seakeeping/maneuvering in waves code TEMPEST, being developed by NSWCCD. This bilge keel force model combines a full unsteady extension of Bollay’s non-linear low aspect ratio lifting surface theory for cases with adequate forward speed with a more conventional approach for cases with zero or low forward speed, using Morison’s equation. This paper presents some representative results from the new bilge keel force model for a surface combatant for various roll amplitudes, roll periods, and forward speeds.
KeywordsBilge-keel forces Time-domain seakeeping Unsteady lifting surface theory
The development of the bilge keel model referred to in this paper was done initially with support from NAVSEA SE/TA funds (James Webster, Program Manager) and later support from ONR (Dr. Pat Purtell, Program Manager). Dr. William Belknap and Dr. Arthur Reed at NSWCCD were the technical monitors for the development of this bilge keel model. Simmy Willemann and Brian Petersen of APS assisted with the calculations shown in this paper. The opinions expressed here are those of the author.
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