Homogenisation method for the modal analysis of tube bundle with fluid–structure interaction modelling

2008 ◽  
Vol 44 (6-7) ◽  
pp. 323-333 ◽  
Author(s):  
Jean-François Sigrist ◽  
Daniel Broc
Keyword(s):  
Modal Analysis ◽  
Tube Bundle ◽  
Fluid Structure Interaction ◽  
Fluid Structure ◽  
Structure Interaction ◽  
Interaction Modelling

Investigation of Numerical Methods for Modal Analysis of a Tube Bundle With Fluid-Structure Interaction

2007 ◽  
Author(s):  
Jean-Franc¸ois Sigrist ◽  
Daniel Broc
Keyword(s):  
Modal Analysis ◽  
Pressure Vessel ◽  
Seismic Analysis ◽  
Tube Bundle ◽  
Fluid Structure Interaction ◽  
Homogenization Method ◽  
Fluid Structure ◽  
Structure Interaction ◽  
Internal Structures ◽  
Homogenization Methods

Seismic analysis of tube bundle is of paramount importance in the safety assessment of nuclear installations. These analyses require in particular the calculation of frequency, mode shape and effective mass of the system eigenmodes. As fluid-structure interaction effects can significantly affect dynamic behaviour of immersed structures, the numerical modeling of the tube bundle has to take into account FSI. A complete modeling of heat exchangers (including pressure vessel, tubes and fluid) is not accessible to the engineer for industrial design studies. In the past decades, homogenization methods have been studies and developed in order to model tubes and fluid through an equivalent continuous media, thus avoiding the tedious task to mesh all structure and fluid sub-domains within the tube bundle. Few of these methods have nonetheless been implemented in industrial finite element codes. In previous papers (Sigrist & Broc, Pressure Vessel and Piping, Vancouver, July 2006), a homogenization method has been developed and applied to an industrial case for the modal analysis of a nuclear rector with internal structures and coupling effects modeling. The present paper aims at investigating the application of the proposed method for the dynamic analysis of tube bundle. The homogenization method is compared with direct and indirect fluid-structure coupled methods for the calculation of eigenmode frequencies, shapes and modal masses.

Overview of DCNS Methodology on Fluid-Structure Interaction Modelling in Nuclear Pressure Vessels

2009 ◽  
Author(s):  
Jean-Franc¸ois Sigrist
Keyword(s):  
Dynamic Analysis ◽  
Nuclear Reactor ◽  
Tube Bundle ◽  
Fluid Structure Interaction ◽  
Pressure Vessels ◽  
Coupled Analysis ◽  
Element Analysis ◽  
Fluid Structure ◽  
Structure Interaction ◽  
Interaction Modelling

The design of nuclear pressure vessel requires the description of various dynamic effects, among which fluid-structure interaction. The present paper gives on overview of DCNS R&D methodology for fluid-structure interaction modelling in nuclear pressure vessels: a global R&D program has been launched by DCNS within a collaborative framework, or the application of numerical methods in FSI to the dynamic analysis of nuclear propulsion systems (nuclear reactors and steam generators). Two applications are proposed in the paper as a conclusive example of this R&D program. 1) The dynamic analysis of a nuclear reactor with FSI is made possible by the implementation of the so-called (u, p, φ) formulation within the ANSYS code [J.F. Sigrist, S. Garreau, Dynamic Analysis of Fluid-Structure Interaction Problems with Spectral Method Using Pressure-Based Finite Elements, Finite Element Analysis in Design, 43 (4), 287–300, 2007] allowing the application of modal methods in the context of coupled fluid-structure systems; importance of FSI in the dynamic behaviour of a nuclear reactor are underlined by a fully coupled analysis. 2) The dynamic analysis of a steam generator with FSI is made possible by the implementation of an homogenisation technique within the CASTEM code [J.F. Sigrist, D. Broc, Dynamic Analysis of a Tube Bundle with Fluid-Structure Interaction Modelling Using a Homogenisation Method, Computer Methods in Applied Mechanics and Engineering, 197 (9–12), 1080–1099, 2008] allowing the description of the interactions between the confined fluid and inner structures and tube bundle in a straightforward manner.

Fluid-Structure Interaction Effects Modeling for the Modal Analysis of a Steam Generator Tube Bundle

2009 ◽  
Vol 131 (3) ◽  
Author(s):  
Jean-François Sigrist ◽  
Daniel Broc
Keyword(s):  
Modal Analysis ◽  
Steam Generator ◽  
Pressure Vessel ◽  
Seismic Analysis ◽  
Tube Bundle ◽  
Fluid Structure Interaction ◽  
Interaction Effects ◽  
Homogenization Method ◽  
Fluid Structure ◽  
Structure Interaction

Seismic analysis of steam generator is of paramount importance in the safety assessment of nuclear installations. These analyses require, in particular, the calculation of frequency, mode shape, and effective modal mass of the system eigenmodes. As fluid-structure interaction effects can significantly affect the dynamic behavior of immersed structures, the numerical modeling of the steam generator has to take into account FSI. A complete modeling of heat exchangers (including pressure vessel, tubes, and fluid) is not accessible to the engineer for industrial design studies. In the past decades, homogenization methods have been studied and developed in order to model tubes and fluid through an equivalent continuous media, thus avoiding the tedious task to mesh all structure and fluid subdomains within the tube bundle. Few of these methods have nonetheless been implemented in industrial finite element codes. In a previous paper (Sigrist, et al., 2007, “Fluid-Structure Interaction Effects Modeling for the Modal Analysis of a Nuclear Pressure Vessel,” J. Pressure Vessel Technol., 123, pp. 1–6), a homogenization method has been applied to an industrial case for the modal analysis of a nuclear rector with internal structures and coupling effects modeling. The present paper aims at investigating the extension of the proposed method for the dynamic analysis of tube bundles with fluid-structure interaction modeling. The homogenization method is compared with the classical coupled method in terms of eigenfrequencies, eigenmodes, and effective modal masses.

Fluid-structure interaction modelling of parachute soft-landing dynamics

2005 ◽  
Vol 47 (6-7) ◽  
pp. 619-631 ◽  
Author(s):  
Keith Stein ◽  
Tayfun E. Tezduyar ◽  
Sunil Sathe ◽  
Richard Benney ◽  
Richard Charles
Keyword(s):  
Fluid Structure Interaction ◽  
Soft Landing ◽  
Fluid Structure ◽  
Structure Interaction ◽  
Interaction Modelling

A Homogenization Method for the Modal Analysis of a Nuclear Reactor With Fluid-Structure Interaction

2006 ◽  
Author(s):  
Jean-Franc¸ois Sigrist ◽  
Daniel Broc
Keyword(s):  
Modal Analysis ◽  
Nuclear Reactor ◽  
Mass Operator ◽  
Fluid Structure Interaction ◽  
Homogenization Method ◽  
Theoretical Point ◽  
Element Discretization ◽  
Fluid Structure ◽  
Structure Interaction ◽  
Internal Structures

The present paper exposes a homogenization method developed in order to perform the modal analysis of a nuclear reactor with fluid-structure interaction effects. The homogenization approach is used in order to take into account the presence of internal structures within the pressure vessel. A homogenization method is proposed in order to perform a numerical calculation of the frequencies and modal masses for the eigenmodes of the coupled fluid-structure problem. The technique allows the use of a simplified fluid-structure model that takes into account the presence of internal structures: the theory bases are first recalled, leading to a new formulation of the fluid-structure coupled problem. The finite element discretization of the coupled formulation leads to the modification of the classical fluid-structure interaction operators. The consistency of the formulation is established from a theoretical point of view by evaluating the total mass of the coupled system with the fluid and structure mass operator, and the modified added mass operator. The method is tested and validated on a 2D case (two concentric cylinders with periodical rigid inclusions within the annular space) and applied on the industrial case. A complete modal analysis (calculation of frequencies and modal masses) is performed on a simplified geometry of a nuclear reactor with and without internal structures. Numerical results are then compared and discussed, and the influence of the internal structures on the fluid-structure coupled phenomenon is highlighted.

Modal Analysis of Fluid-Structure Interaction in a Bent Pipeline

2016 ◽  
Author(s):  
Gudrun Mikota ◽  
Rainer Haas ◽  
Evgeny Lukachev
Keyword(s):  
Modal Analysis ◽  
Degrees Of Freedom ◽  
Coupling Effect ◽  
Fluid Structure Interaction ◽  
Interaction Model ◽  
Coupling Mechanism ◽  
Fluid Structure ◽  
Structure Interaction ◽  
Resonance Coupling ◽  
Measured Frequency Response

Fluid-structure interaction in a bent pipeline is investigated by modal methods. Measured frequency response functions between flow rate excitation and pressure response indicate a coupling effect near the third pipeline resonance. Using modal coordinates for the hydraulic and the mechanical subsystems, a two-degrees-of-freedom study of resonance coupling is carried out. An experimental modal analysis of the coupled hydraulic-mechanical system confirms the predicted resonance splitting; it illustrates the coupling mechanism and shows the relevant mechanical part. An analytical fluid-structure interaction model succeeds in reproducing the measured coupling effect. This model is also used for modification prediction; it demonstrates that an appropriate assembly of mass and damping on the pipeline can help to reduce hydraulic resonance amplitudes.

Simulation of Fluid Flow Using Reduced-Order Modeling by POD Approach Applied to a Fixed Tube Bundle System

2010 ◽  
Author(s):  
Marie Pomarede ◽  
Erwan Liberge ◽  
Aziz Hamdouni ◽  
Elisabeth Longatte ◽  
Jean-Franc¸ois Sigrist
Keyword(s):  
Dynamic Analysis ◽  
Steam Generator ◽  
Tube Bundle ◽  
Fluid Structure Interaction ◽  
Reduced Model ◽  
Steam Generator Tube ◽  
Fluid Structure ◽  
Reduced Order ◽  
Structure Interaction ◽  
Tube Bundles

Tube bundles in steam boilers of nuclear power plants and nuclear on-board stokehold are known to be exposed to high levels of vibrations. This coupled fluid-structure problem is very complex to numerically set up, because of its three-dimensional characteristics and because of the large number of degrees of freedom involved. A complete numerical resolution of such a problem is currently not viable, all the more so as a precise understanding of this system behaviour needs a large amount of data, obtained by very expensive calculations. We propose here to apply the now classical reduced order method called Proper Orthogonal Decomposition to a case of 2D flow around a tube bundle. Such a case is simpler than a complete steam generator tube bundle; however, it allows observing the POD projection behaviour in order to project its application on a more realistic case. The choice of POD leads to reduced calculation times and could eventually allow parametrical investigations thanks to a low data quantity. But, it implies several challenges inherent to the fluid-structure characteristic of the problem. Previous works on the dynamic analysis of steam generator tube bundles already provided interesting results in the case of quiescent fluid [J.F. Sigrist, D. Broc; Dynamic Analysis of a Steam Generator Tube Bundle with Fluid-Structure Interaction; Pressure Vessel and Piping, July 27–31, 2008, Chicago]. Within the framework of the present study, the implementation of POD in academic cases (one-dimensional equations, 2D-single tube configuration) is presented. Then, firsts POD modes for a 2D tube bundle configuration is considered; the corresponding reduced model obtained thanks to a Galerkin projection on POD modes is finally presented. The fixed case is first studied; future work will concern the fluid-structure interaction problem. Present study recalls the efficiency of the reduced model to reproduce similar problems from a unique data set for various configurations as well as the efficiency of the reduction for simple cases. Results on the velocity flow-field obtained thanks to the reduced-order model computation are encouraging for future works of fluid-structure interaction and 3D cases.

Fluid Structure Interaction Modelling

2004 ◽  
Author(s):  
Jason J. Dale ◽  
A. E. Holdo̸
Keyword(s):  
Thermal Stresses ◽  
Fluid Structure Interaction ◽  
Research Area ◽  
Solution Procedure ◽  
Fluid Structure ◽  
Structure Interaction ◽  
Interaction Modelling ◽  
Active Research ◽  
Displacement Based ◽  
Volume Method

Numerical modeling of fluid/structure interaction (FSI) falls into the multi-physics domain and has significant importance in many engineering problems. It is an active research area in the field of computational mechanics and examples are found in diverse applications such as aeronautics, biomechanics and the offshore industries. As such, Computational Fluid Dynamics (CFD) and Finite Element (FE) analysis techniques have continuously evolved into this field. This paper presents one such technique and focuses on the further developments of a displacement based finite volume method previously presented by the author, in particular, its ability to now predict fixed displacement, normal, shear and thermal stresses and strains within a single CFD program. An advantage of this method is that a single solution procedure has the potential to be employed to predict both fluid, structural and fluid/structure interaction effects simultaneously.

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