Assessment study of a Domain-Decomposition strategy for marine applications (Contributo in atti di convegno)

Type
Label
  • Assessment study of a Domain-Decomposition strategy for marine applications (Contributo in atti di convegno) (literal)
Anno
  • 2012-01-01T00:00:00+01:00 (literal)
Alternative label
  • Greco M. 1,2,3; Colicchio G. 1,2; Lugni C. 1,2 (2012)
    Assessment study of a Domain-Decomposition strategy for marine applications
    in 27th Int. Workshop on Water Waves and Floating Bodies, Copenhagen, Denmark, 22-25 April 2012
    (literal)
Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#autori
  • Greco M. 1,2,3; Colicchio G. 1,2; Lugni C. 1,2 (literal)
Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#pagineTotali
  • 4 (literal)
Note
  • PuM (literal)
Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#affiliazioni
  • 1 INSEAN, Italian Ship Model Basin, Roma - Italy. 2 Centre for Ships and Ocean Structures (CeSOS), NTNU, Trondheim - Norway. 3 Department of Marine Technology, NTNU, Trondheim - Norway (literal)
Titolo
  • Assessment study of a Domain-Decomposition strategy for marine applications (literal)
Http://www.cnr.it/ontology/cnr/pubblicazioni.owl#isbn
  • 978-87-90416-69-0 (literal)
Abstract
  • Greco et al. (2011) tried to identify the proper numerical choices for the development of a three-dimensional DomainDecomposition (DD) strategy. It aims to study the violent interaction of FPSO ships with head-sea regular waves. The present work represents a contribution in this direction. The under development DD solver combines a Boundary Element Method (BEM) for the global linear seakeeping analysis in frequency domain with a Navier-Stokes (NS) method for the flow investigation in an inner sea region containing the forward portion of the vessel. In this region, water shipping and slamming events can be caused by the liquid-structure interactions, while it is assumed that the rest of the fluid domain can be suitably described by the linear potential-flow solver. Within the NS solver, a Projection method is adopted with a finite-difference scheme on an Eulerian grid and a Predictor-Corrector scheme for the time evolution. The solver is accurate to the second order. The evolution of the free surface is captured by means of a Level-Set (LS) technique updating in time the normal distance (with-sign) from the water-air interface. Moreover the influence of the air on the water is neglected and the velocity field is smoothly extended from the liquid to the gas domain. The non-slip bodyboundary condition is enforced through a hybrid Eulerian-Lagrangian approach combining the body LS function ?body (positive in the fluid) with point markers moving with the body and initially defined on a uniform grid four times finer than the minimum mesh size in the computational grid and within a band across the body surface six times larger than the maximum mesh size of the computational grid. The body points evolve in time carrying with them their distance from the body surface and this allows a more accurate estimate of ?body on the Eulerian grid by interpolation from the markers. The coupling between the outer and inner solvers is implemented as a weak and a strong strategy. In the former case, the information travels from the outer to the inner solver but not vice versa; in the latter, the information travels back and fourth. The NS solver needs initial and boundary conditions in terms of velocity, pressure and free surface elevation in the fluid and the body-boundary condition along the solid surface. The seakeeping solver feels the nonlinearities and possible viscous effects predicted in the inner domain through local and global loads acting on the ship portion inside this region. The rest of the ship hull is assumed to be subjected to the loads provided by the potential-flow outer solver. For a freely-floating vessel, the inner-domain global loads are introduced in the body-motion equations, so that the ship motion can be affected by the inner-flow features that can alter the flow pattern in the inner domain in return. (literal)
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