URANS Investigation of Ship Roll Motion Damping Using Bilge Keels

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Authors
  1. Counsil, J.
  2. Boulama, K.G.
Corporate Authors
Defence Research and Development Canada, Atlantic Research Centre, Halifax NS (CAN);Royal Military Coll of Canada, Kingston ONT (CAN) Dept of Mechanical Engineering
Abstract
It is widely accepted in ship hydrodynamics research that rolling is the least understood of the six degrees of freedom. Bilge keels are passive devices which are appended to the hull of a ship in order to increase the ship’s natural roll damping, thereby reducing the amplitude of roll motions. The optimum size of these bilge keels for effective roll damping and the influence of the roll amplitude on the performance of the bilge keels require careful research. Computational Fluid Dynamics (CFD) and particularly Unsteady Reynolds- Averaged Navier-Stokes methods (URANS) have some advantages over experimental methods for their cost, simplicity of parameterization, and data extraction, although their use in roll damping investigations is still in its infancy due to the inherent difficulty in modelling turbulence, free-surface interactions and moving meshes, among other considerations. Traditional empirically derived analytical methods are still in use today due to their ease of use, though their prediction abilities in the presence of strong viscous interactions are debatable. DRDC Atlantic has partnered with the Royal Military College of Canada as part of ongoing research into bilge keel roll damping. Using their in-house software, DRDC has obtained excellent results for many hydrodynamics and maneuvering cases though viscous roll damping still proves challenging. Hence, the commercial CFD code STAR-CCM+ is employed here to study a variety of bilge keel spans at different roll
Keywords
bilge keels;computational fluid dynamics;roll;roll damping;seakeeping;ship motion
Report Number
DRDC-RDDC-2016-C134 — Contract Report
Date of publication
01 Apr 2016
Number of Pages
53
DSTKIM No
CA042456
CANDIS No
803639
Format(s):
Electronic Document(PDF)

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