Numerical Simulation of Dynamic Response of Structure Caused by Wave Impact Pressure Using an Eulerian Scheme With Lagrangian Particles

2009 ◽  
Author(s):  
Hidemi Mutsuda ◽  
Yasuaki Doi
Keyword(s):  
Free Surface ◽  
Elastic Deformation ◽  
Wave Breaking ◽  
Fluid Structure Interaction ◽  
Experimental Results ◽  
Impact Pressure ◽  
Wave Impact ◽  
Fluid Structure ◽  
Structure Interaction ◽  
Lagrangian Particles

This study focuses on the development of computational techniques for computing fluid-structure interaction with wave breaking. This is of practical relevance in both ocean, and ship hydrodynamics. This paper also presents a prediction of the local highly pressure load impacting on a rigid and elastic structure caused by fluid force including impact pressure. We have developed a new numerical scheme that combines a Eulerian scheme with Lagrangian particles, i.e. free surface particles and SPH particles, to compute fluid-structure interaction caused by impact pressure. In this model, we employed two kinds of particles. One is free surface particle located near the free surface to capture air-water interface accurately. The other one is SPH particle to compute solid motion and elastic deformation. The air-water mixing flow is treated on a fixed Eulerian grid with the free surface particles to rebuild the density function for capturing the interface in filamentary regions that are under-resolved. Conversely, the structure is solved using the particle method, SPH. These Lagrangian particles are useful and available to capture the interface between different phases. In this paper, the proposed method was applied to the water entry problems of a V-shaped wedge, a horizontal flat-plate, a circular cylinder, an elastic cylindrical shell and impact pressure acting on an elastic wall caused by wave breaking. The free surface and elastic deformation are compared with both numerical and experimental results. The pressure and strain predictions are also compared with experimental results obtained by other researchers.

Fluid Structure Interaction Simulations Involving Free Surface

2018 ◽  
Author(s):  
H. R. Díaz-Ojeda ◽  
L. M. González ◽  
F. J. Huera-Huarte
Keyword(s):  
Free Surface ◽  
Circular Cylinder ◽  
Fluid Structure Interaction ◽  
Flexible Structure ◽  
Fluid Structure ◽  
Structure Interaction ◽  
Classical Fluid ◽  
Simple Geometry ◽  
Different Depths

The aim of this paper is to evaluate how much affects the presence of gravity and free-surface to a flexible structure in a classical fluid structure interaction (FSI) problem typically found in off-shore problems and other oceanic applications. The base problem selected is the Turek benchmark case where a deformable plate is attached to the wake of a circular cylinder. To focus on the differences of considering free surface, a simple geometry has been selected and two different situations have been studied: the first one is the classical Turek benchmark, the second is a similar geometry but adding gravity and free surface. The free surface problem was studied placing the structure at different depths and monitoring the deformation and forces on the structure.

Natural Frequencies of Centrifugal Compressor Impellers for High Density Gas Applications

2008 ◽  
Author(s):  
Yohei Magara ◽  
Mitsuhiro Narita ◽  
Kazuyuki Yamaguchi ◽  
Naohiko Takahashi ◽  
Tetsuya Kuwano
Keyword(s):  
Centrifugal Compressor ◽  
Natural Frequencies ◽  
Fluid Structure Interaction ◽  
Mass Effect ◽  
Added Mass ◽  
High Density ◽  
Experimental Results ◽  
Density Condition ◽  
Fluid Structure ◽  
Structure Interaction

Characteristics of natural frequencies of an impeller and an equivalent disc were investigated in high-density gas to develop a method for predicting natural frequencies of centrifugal compressor impellers for high-density gas applications. The equivalent disc had outer and inner diameters equal to those of the impeller. We expected that natural frequencies would decrease with increasing the gas density because of the added-mass effect. However, we found experimentally that some natural frequencies of the impeller and the disc in high-density gas decreased but others increased. Moreover, we observed, under high-density condition, some resonance frequencies that we did not observe under low-density condition. These experimental results cannot be explained by only the added-mass effect. For simplicity, we focused on the disc to understand the mechanism of the behavior of natural frequencies. We developed a theoretical analysis of fluid-structure interaction considering not only the mass but also stiffness of gas. The analysis gave a qualitative explanation of the experimental results. In addition, we carried out a fluid-structure interaction analysis using the finite element method. The behavior of natural frequencies of the disc in high-density gas was predicted with errors less than 6%.

scholarly journals A Multiphysics Multiscale 3-D Computational Wave Basin Model for Wave Impact Load on a Cylindrical Structure

2009 ◽  
Vol 4 (6) ◽  
pp. 450-461 ◽  
Author(s):  
Solomon C. Yim ◽  
◽  
Wenbin Zhang
Keyword(s):  
Water Surface ◽  
Fluid Structure Interaction ◽  
Surface Elevation ◽  
Horizontal Force ◽  
Wave Impact ◽  
Fluid Structure ◽  
Cylindrical Structure ◽  
Structure Interaction ◽  
Wave Basin ◽  
Overturning Moment

A multiphysics multiscale finite-element based nonlinear computational wave basin (CWB) model is developed using LS-DYNA. Its predictive capability is calibrated using a large-scale fluid-structure interaction experiment conducted in a 3-dimensional wave basin to determine wave impact on a cylindrical structure. This study focuses on evaluating CWB accuracy using two wave excitation conditions — plane and focused solitary waves — and two cylinder arrangements — single and multiple cylinders. Water surface elevation and water particle velocity are predicted numerically for the fluid domain, obtaining horizontal force, overturning moment, and dynamic pressure on the cylindrical structure and calibrated against experimental measurement. The CWB model predicts wave motion characteristics — water surface elevation and velocity, and integrated structural response — horizontal force and overturning moment, for the given wave conditions well. Computation time increases and the predictive accuracy decreases as nonlinear fluid-structure interaction becomes increasingly complex. A study of computation settings for improving computation performance showed that a high-performance parallel-computing hardware platform is needed to model details of highly nonlinear physics of fluid flow including wave breaking and turbulence.

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