4 research outputs found
A BEM-ISOGEOMETRIC method for the ship wave-resistance problem
In the present work IsoGeometric Analysis is applied to the solution of the Boundary
Integral Equation associated with the Neumann-Kelvin problem and the calculation of the
wave resistance of ships. As opposed to low-order panel methods, where the body is
represented by a large number of quadrilateral panels and the velocity potential is assumed
to be piecewise constant (or approximated by low degree polynomials) on each panel, the
isogeometric concept is based on exploiting the same NURBS basis, used for representing
exactly the body geometry, for approximating the singularity distribution (and, in general,
the dependent physical quantities). In order to examine the accuracy of the present method,
numerical results obtained in the case of submerged and surface piercing bodies are
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compared against analytical solutions, experimental data and predictions provided by the
low-order panel or other similar methods appeared in the pertinent literature, illustrating
the superior efficiency of the isogeometric approach. The present approach by applying
Isogeometric Analysis and Boundary Element Method to the linear NK problem has the
novelty of combining modern CAD systems for ship-hull design with computational
hydrodynamics tools
Isogeometric Boundary-Element Analysis for the Wave-Resistance Problem using T-splines
In this paper we couple collocated Boundary Element Methods (BEM) with unstructured analysis suitable
T-spline surfaces for solving a linear Boundary Integral Equation (BIE) arising in the
context of a ship-hydrodynamic problem, namely the so-called Neumann-Kelvin problem, following
the formulation by Brard (1972) [1] and Baar & Price (1988) [2]. The local-refinement capabilities
of the adopted T-spline bases, which are used for representing both the geometry of the hull and
approximating the solution of the associated BIE, in accordance with the Isogeometric concept
proposed by Hughes et al. (2005) [3], lead to a solver that achieves the same error level for many
fewer degrees of freedom as compared with the corresponding NURBS-based Isogeometric-BEM
solver recently developed in Belibassakis et al. (2013) [4]. In this connection, this paper makes a
step towards integrating modern CAD representations for ship-hulls with hydrodynamic solvers of
improved accuracy and efficiency, which is a prerequisite for building efficient ship-hull optimizers
Isogeometric boundary-element analysis for the wave-resistance problem using T-splines
In this paper we couple collocated Boundary Element Methods (BEM) with unstructured analysis-suitable T-spline surfaces for solving a linear Boundary Integral Equation (BIE) arising in the context of a ship-hydrodynamic problem, namely the so-called Neumann–Kelvin problem, following the formulation by Brard (1972) and Baar and Price (1988). The local-refinement capabilities of the adopted T-spline bases, which are used for representing both the geometry of the hull and approximating the solution of the associated BIE, in accordance with the Isogeometric concept proposed by Hughes et al. (2005), lead to a solver that achieves the same error level for many fewer degrees of freedom as compared with the corresponding NURBS-based Isogeometric-BEM solver recently developed in Belibassakis et al. (2013). In this connection, this paper makes a step towards integrating modern CAD representations for ship-hulls with hydrodynamic solvers of improved accuracy and efficiency, which is a prerequisite for building efficient ship-hull optimizers
A BEM-IsoGeometric method with application to the wavemaking resistance problem of ships at constant speed
In the present work IsoGeometric Analysis (IGA), initially proposed by Hughes et al (2005), is applied to the solution of the boundary integral equation associated with the Neumann-Kelvin (NK) problem and the calculation of the wave resistance of ships, following the formulation by Brard (1972) and Baar & Price (1988). As opposed to low-order panel methods, where the body is represented by a large number of quadrilateral panels and the velocity potential is assumed to be piecewise constant (or approximated by low degree polynomials) on each panel, the isogeometric concept is based on exploiting the NURBS basis, which is used for representing exactly the body geometry and adopts the very same basis functions for approximating the singularity distribution (or in general the dependent physical quantities). In order to examine the accuracy of the present method, in a previous paper Belibassakis et al (2009), numerical results obtained in the case of submerged bodies are compared against analytical and benchmark solutions and low-order panel method predictions, illustrating the superior efficiency of the isogeometric approach. In the present paper we extent previous analysis to the case of wavemaking resistance problem of surface piercing bodies. The present approach, although focusing on the linear NK problem which is more appropriate for thin ship hulls, it carries the IGA novelty of integrating CAD systems for shiphull design with computational hydrodynamics solvers