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Finite Element Analysis for Evaluation of Viscous and Eccentricity Effects on Fluid Added Mass and Damping

유체 부가질량 및 감쇠 결정시 점성 및 편심 영향에 대한 유한요소해석

  • 구경회 (한국원자력연구소) ;
  • 이재한 (한국원자력연구소)
  • Published : 2003.04.01

Abstract

In general, simple fluid added mass method is used for the seismic and vibration analysis of the immersed structure to consider the fluid-structure interaction effect. Actually, the structural response of the immersed structure can be affected by both the fluid added mass and damping caused by the fluid viscosity. These variables appeared as a consistent matrix form with the coupling terms. In this paper, finite element formula for the inviscid fluid case and viscous fluid case are derived from the linearized Navier Stoke's equations. Using the finite element program developed in this paper, the analyses of fluid added mass and damping for the hexagon core structure of the liquid metal reactor are carried out to investigate the effect of fluid viscosity with variation of the fluid gap and Reynolds number. From the analysis results, it is verified that the viscosity significantly affects the fluid added mass and damping as the fluid gap size decrease. From the analysis results of eccentricity effect on the fluid added mass and damping of the concentric cylinders, the fluid added mass increase as the eccentricity increases, however the fluid damping increases only when the eccentricity is very severe.

Keywords

fluid-structure interaction;fluid viscosity;fluid added mass;fluid damping;core seismic analysis

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