Solving generalized eigenvalue problems for large scale fluid-structure computational models with mid-power computers

Capiez‐Lernout

Journal of Fluids and Structures

et al. 2019

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Using an advanced nonlinear fluid-structure reduced-order computational model, this work revisits and explains a resonance of the free surface of water contained in a thin elastic cylindrical tank, which was experimentally exhibited by Lindholm, 1962 and Abramson, 1966. The proposed simulation model allows the experimental setup to be reproduced. The structure undergoes large displacements and large deformations (geometrical nonlinear effects of the structure) that play an important role on the liquid vibrations. The experimental setup is simulated using a large-scale numerical model of the elastic cylindrical tank partially filled with water that is considered as a compressible fluid and that takes into account surface tension and sloshing effects. The results show that for a frequency external excitation in the frequency band [500, 2,500] Hz of the fluid-structure system, unexpected high-amplitude sloshing vibrations are observed in the frequency band [0, 150] Hz. The observed phenomenon, which cannot be reproduced with a linear fluid-structure model, is explained by the transfer of the vibrational energy from the frequency band of excitation into a low-frequency band (and then exciting the first sloshing modes) by a non-direct coupling mechanism between the structural modes and the sloshing modes.

Section: Construction Of the Nonlinear Reduced-order Computational Modelmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Revisiting the experiment of a free-surface resonance of a liquid in a vibration tank using a nonlinear fluid–structure computational model

Capiez‐Lernout

Journal of Fluids and Structures

et al. 2019

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“…For solving the three generalized eigenvalue problems for large scale fluid-structure computational models with mid-power computers, we refer the reader to [63] in which all the details are given, for which the matrices of the generalized eigenvalue problems must be those introduced in Section 5.3.1, that is to say, using quadratic finite elements.…”

Section: Reduced-order Computational Model For the Coupled Systemmentioning

confidence: 99%

Novel formulation for the effects of sloshing with capillarity on elastic structures in linear dynamics

Ohayon

Numerical Meth Engineering

et al. 2019

This paper is devoted to the linear dynamics of liquid-structure interactions for an elastic structure filled with compressible liquid (acoustic liquid), with sloshing and with capillarity effects on the free surface in presence of a gravity field. The objective is to detail the formulation and to quantify the role played by the elasticity in the neighborhood of the triple contact line between the free surface of the compressible liquid and the elastic structure in presence of sloshing and capillarity effects. Most of the works consider that the structure is totally not deformable (rigid tank). Nevertheless, for taking into account the elasticity of the tank, some works have introduced an approximation, which consists in considering a locally undeformable structure in the neighborhood of the triple contact line. The theory presented requires the use of quadratic finite elements for discretizing a new introduced boundary condition. An application has specifically been constructed and presented for quantifying the role played by the elasticity of the structure in the neighborhood of the triple contact line.

“…Such computation on mid-power computers can be very challenging when large finite element meshes are involved. The original computational strategy [5] that allows for circumventing these difficulties is used in this analysis. The nonlinear reduced-order model is then written as…”

Section: Description Of the Computational Modelmentioning

confidence: 99%

Nonlinear Dynamical Analysis for Coupled Fluid-Structure Systems

Capiez‐Lernout

Nonlinear Structures and Systems, Volume 1

et al. 2019

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The present research concerns the numerical dynamical analysis in elasto-acoustics, taking into account the geometrical nonlinearities induced by the large displacements/deformations of the structure and assuming the internal acoustic fluid occupying an internal cavity coupled to the structure to remain in a linear range of vibration. More particularly, the modeling includes sloshing and capillarity effects on the free surface. A numerical application is presented.