• 제목/요약/키워드: Second order

검색결과 12,939건 처리시간 0.037초

Prediction of the wave induced second order vertical bending moment due to the variation of the ship side angle by using the quadratic strip theory

  • Kim, Seunglyong;Ryue, Jungsoo;Park, In-Kyu
    • International Journal of Naval Architecture and Ocean Engineering
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    • 제10권3호
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    • pp.259-269
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    • 2018
  • In this study, the second order bending moment induced by sea waves is calculated using the quadratic strip theory. The theory has the fluid forcing terms including the quadratic terms of the hydrodynamic forces and the Froude-Krylov forces. They are applied to a ship as the external forces in order to estimate the second order ship responses by fluid forces. The sensitivity of the second order bending moment is investigated by implementing the quadratic terms by varying the ship side angle for two example ships. As a result, it was found that the second order bending moment changes significantly by the variation of the ship side angle. It implies that increased flare angles at the bow and the stern of ships being enlarged would amplify their vertical bending moments considerably due to the quadratic terms and may make them vulnerable to the fatigue.

AN ENERGY-STABLE AND SECOND-ORDER ACCURATE METHOD FOR SOLVING THE INCOMPRESSIBLE NAVIER-STOKES EQUATIONS

  • KIM, JEONGHO;JUNG, JINWOOK;PARK, YESOM;MIN, CHOHONG;LEE, BYUNGJOON
    • Journal of the Korean Society for Industrial and Applied Mathematics
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    • 제23권2호
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    • pp.93-114
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    • 2019
  • In this article, we introduce a finite difference method for solving the Navier-Stokes equations in rectangular domains. The method is proved to be energy stable and shown to be second-order accurate in several benchmark problems. Due to the guaranteed stability and the second order accuracy, the method can be a reliable tool in real-time simulations and physics-based animations with very dynamic fluid motion. We first discuss a simple convection equation, on which many standard explicit methods fail to be energy stable. Our method is an implicit Runge-Kutta method that preserves the energy for inviscid fluid and does not increase the energy for viscous fluid. Integration-by-parts in space is essential to achieve the energy stability, and we could achieve the integration-by-parts in discrete level by using the Marker-And-Cell configuration and central finite differences. The method, which is implicit and second-order accurate, extends our previous method [1] that was explicit and first-order accurate. It satisfies the energy stability and assumes rectangular domains. We acknowledge that the assumption on domains is restrictive, but the method is one of the few methods that are fully stable and second-order accurate.

EIGENVALUES OF SECOND-ORDER VECTOR EQUATIONS ON TIME SCALES WITH BOUNDARY VALUE CONDITIONS

  • Wang, Yi
    • Journal of applied mathematics & informatics
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    • 제29권1_2호
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    • pp.267-277
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    • 2011
  • This paper is concerned with eigenvalues of second-order vector equations on time scales with boundary value conditions. Properties of eigenvalues and matrix-valued solutions are studied. Relationships between eigenvalues of different boundary value problems are discussed.

Moment-curvature relationships to estimate deflections and second-order moments in wind-loaded RC chimneys and towers

  • Menon, Devdas
    • Wind and Structures
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    • 제1권3호
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    • pp.255-269
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    • 1998
  • Second-order moments of considerable magnitude arise in tall and slender RC chimneys and towers subject to along-wind loading, on account of eccentricities in the distributed self-weight of the tower in the deflected profile. An accurate solution to this problem of geometric nonlinearity is rendered difficult by the uncertainties in estimating the flexural rigidity of the tower, due to variable cracking of concrete and the 'tension stiffening' effect. This paper presents a rigorous procedure for estimating deflections and second-order moments in wind-loaded RC tubular towers. The procedure is essentially based on a generalised formulation of moment-curvature relationships for RC tubular towers, derived from the experimental and theoretical studies reported by Schlaich et al. 1979 and Menon 1994 respectively. The paper also demonstrates the application of the proposed procedure, and highlights those conditions wherein second-order moments become too significant to be overlooked in design.