A fast-running CFD formulation for unsteady ship maneuvering performance prediction. (1st May 2016)

• Record Type: Journal Article
• Authors: Woolliscroft, M.O.; Maki, K.J.
• Is Part Of: Ocean engineering. Volume 117(2016)
• Page Start: 154
• Page End: 162
• Publication Date: 2016-05-01
• Subjects: Maneuvering prediction -- Early-stage design -- Linearized free-surface -- URANS; Ocean engineering -- Periodicals; Ocean engineering; Periodicals; 620.4162
• DOI: 10.1016/j.oceaneng.2016.03.058
• Languages: English
• ISSNs: 0029-8018

Abstract

Abstract: Maneuvering prediction tools are important resources for naval and commercial ship designers. They can enable designers to determine maneuvering characteristics of a design prior to construction or be useful in redesign if a ship is underperforming. Numerical methods allow for multiple hulls to be compared digitally, so a certain level of optimization can be achieved through evaluating trade-offs among designs before construction. In this paper, a novel maneuvering prediction method is presented that seeks to provide the accuracy available from today state-of-the-art numerical viscous-flow tools but with significantly reduced computational cost. The numerical formulation is based on the unsteady Reynolds-averaged Navier–Stokes (URANS) equations, and the unsteady ship generated waves are represented by the linear free-surface boundary conditions. The URANS equations are solved on an unstructured finite-volume discretization of the fluid domain around the hull and its appendages. The linearized free-surface approximation accounts for first-order wave effects while reducing the necessary extent of the computational domain and level of grid refinement required by fully nonlinear methods that employ an interface-capturing technique. The resulting formulation provides a marked improvement in computational efficiency with respect to nonlinear methods and can empower naval architects to obtain accurate results earlier in the design process. Abstract : Highlights: Ship maneuvering is performed with a URANS/linearized free-surface formulation. The technology offers an efficiency improvement within a necessary ship design step. The novel ALE kinematic condition solved with OpenFOAM is presented. Static and dynamic grid variations are compared for forward speed resistance. Maneuvering results are accurate and obtained in relatively few CPU hours.