scholarly journals On the Choice of Interface Parameters in Robin–Robin Loosely Coupled Schemes for Fluid–Structure Interaction

Fluids ◽  
2021 ◽  
Vol 6 (6) ◽  
pp. 213
Author(s):  
Giacomo Gigante ◽  
Christian Vergara
Keyword(s):  
Fluid Structure Interaction ◽  
Time Discretization ◽  
Mass Effect ◽  
Reduction Factor ◽  
Cylindrical Domain ◽  
Fluid Structure ◽  
Strongly Coupled ◽  
Structure Interaction ◽  
Loosely Coupled ◽  
Interface Parameters

We consider two loosely coupled schemes for the solution of the fluid–structure interaction problem in the presence of large added mass effect. In particular, we introduce the Robin–Robin and Robin–Neumann explicit schemes where suitable interface conditions of Robin type are used. For the estimate of interface Robin parameters which guarantee stability of the numerical solution, we propose a new strategy based on the optimization of the reduction factor of the corresponding strongly coupled (implicit) scheme, by means of the optimized Schwarz method. To check the suitability of our proposals, we show numerical results both in an ideal cylindrical domain and in a real human carotid. Our results showed the effectiveness of our proposal for the calibration of interface parameters, which leads to stable results and shows how the explicit solution tends to the implicit one for decreasing values of the time discretization parameter.

Efficiency of Diffuse and Sharp Interface Strongly Coupled Fluid Structure Interaction Methods in Fixed and Moving Boundaries

2016 ◽  
Author(s):  
Fazlolah Mohaghegh ◽  
H. S. Udaykumar
Keyword(s):  
Fluid Structure Interaction ◽  
Mass Effect ◽  
Sharp Interface ◽  
Diffuse Interface ◽  
Immersed Boundary ◽  
Immersed Boundary Methods ◽  
Time Step ◽  
Fluid Structure ◽  
Strongly Coupled ◽  
Structure Interaction

Efficiency of different types of immersed boundary methods in the fluid structure interaction (FSI) analysis is studied for different cases. Two different formulations of smoothed profile method (SPM) [1, 2] as diffuse interface approaches are compared with the ghost fluid method (GFM) [3, 4] as sharp interface method (SIM) [5]. First, the original SPM which has two pressure Poisson equations (SPM2P) is modified to a novel formulation for SPM with only one pressure Poisson equation (SPM1P) and then validated. The efficiency study is performed for SPM1P, SPM2P and SIM. The results show that when the solid object is fixed, the explicit solution of SIM is faster than the two SPMs. However, when the solid is moving and strongly coupled formulations is used, SPM1P will be the fastest method. It is shown that the efficiency of the strongly coupled formulations depends on the number of subiterations required in each time step to reach the converged implicit solution. SPM1P and SPM2P need less number of subiterations in comparison with SIM and they are faster. When the added mass effect is high, the efficiency of SPM becomes more noticeable as the required number of subiterations is significantly less in SPM. Finally, SPM1P is faster than SPM2P in all cases however, the accuracy of SPM2P in predicting the flow pattern is better than SPM1P.

Dynamics of a Free Heaving and Prescribed Pitching Hydrofoil in a Turbulent Flow, With a Fluid-Structure Interaction Approach

2018 ◽  
Author(s):  
P. Brousseau ◽  
M. Benaouicha ◽  
S. Guillou
Keyword(s):  
Fluid Structure Interaction ◽  
Vertical Displacement ◽  
Rotational Displacement ◽  
Fluid Structure ◽  
Strongly Coupled ◽  
Structure Interaction ◽  
Maximum Angle ◽  
High Maximum ◽  
Oscillating Foil ◽  
Interaction Approach

This paper deals with the dynamics of an oscillating foil, describing a free heaving (vertical displacement) and prescribed pitching (rotational displacement) movement which is computed from its position in two different ways. A fluid-structure interaction approach is chosen, as the physics of the flow and the structure are strongly coupled. The flow is unsteady, turbulent and incompressible. The pressure/velocity problem is solved using SIMPLEC scheme. First, the pitching movement is considered as a given continuous function of the hydrofoil heaving position. Second, the pitching motion is performed alternately at the end of each heave cycle. For each case, two maximum angles of attack and one heaving amplitudes are studied. Preliminary results showed that a high maximum angle of attack generates more lift hydrodynamics force, but also requires more energy to perform the rotation of pitch.

scholarly journals Study on Fluid-Structure Interaction of Flexible Membrane Structures in Wind-Induced Vibration

2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Fangjin Sun ◽  
Donghan Zhu ◽  
Tiantian Liu ◽  
Daming Zhang
Keyword(s):  
Projection Method ◽  
Fluid Structure Interaction ◽  
Initial Pressure ◽  
Projection Methods ◽  
Accurate Solution ◽  
Membranous Structure ◽  
Fluid Structure ◽  
Strongly Coupled ◽  
Structure Interaction ◽  
Modified Projection Method

A strongly coupled monolithic method was previously proposed for the computation of wind-induced fluid-structure interaction of flexible membranous structures by the authors. How to obtain the accurate solution is a key issue for the strongly coupled monolithic method. Projection methods are among the commonly used methods for the coupled solution. In the work here, to impose initial pressure boundary conditions implicitly defined in the original momentum equations in classical projection methods when dealing with large-displacement of membranous structures, a modified factor is introduced in corrector step of classical projection methods and a new modified projection method is obtained. The solution procedures of the modified projection method aimed at strongly coupled monolithic equations are given, and the related equations are derived. The proposed method is applied to the computation of a two-dimensional fluid-structure interaction benchmark case and wind-induced fluid-structure interaction of a three-dimensional flexible membranous structure. The performance and efficiency of the modified projection method are evaluated. The results show that the modified projection methods are valid in the computation of wind-induced fluid-structure interaction of flexible membranous structures, with higher accuracy and efficiency compared with traditional methods. The modified value has little effects on the computation results whereas iteration times has significant effects. Computation accuracy can be improved greatly by increasing iteration times with less increase in computation time and little effects on stability with the modified projection method.

Numerical Investigation of Hydroelastic Response of a Three-Dimensional Deformable Hydrofoil

2020 ◽  
Author(s):  
Saeed Hosseinzadeh ◽  
Kristjan Tabri
Keyword(s):  
Pressure Coefficient ◽  
Fluid Structure Interaction ◽  
Three Dimensional ◽  
Leading Edge ◽  
Elastic Response ◽  
Fluid Structure ◽  
Strongly Coupled ◽  
Structure Interaction ◽  
Lift And Drag ◽  
Hydroelastic Response

The present study is concerned with the numerical simulation of Fluid-Structure Interaction (FSI) on a deformable three-dimensional hydrofoil in a turbulent flow. The aim of this work is to develop a strongly coupled two-way fluid-structure interaction methodology with a sufficiently high spatial accuracy to examine the effect of turbulent and cavitating flow on the hydroelastic response of a flexible hydrofoil. A 3-D cantilevered hydrofoil with two degrees-of-freedom is considered to simulate the plunging and pitching motion at the foil tip due to bending and twisting deformation. The defined problem is numerically investigated by coupled Finite Volume Method (FVM) and Finite Element Method (FEM) under a two-way coupling method. In order to find a better understanding of the dynamic FSI response and stability of flexible lifting bodies, the fluid flow is modeled in the different turbulence models and cavitation conditions. The flow-induced deformation and elastic response of both rigid and flexible hydrofoils at various angles of attack are studied. The effect of three-dimension body, pressure coefficient at different locations of the hydrofoil, leading-edge and trailing-edge deformation are presented and the results show that because of elastic deformation, the angle of attack increases and it lead to higher lift and drag coefficients. In addition, the deformations are generally limited by stall condition and because of unsteady vortex shedding, the post-stall condition should be considered in FSI simulation of deformable hydrofoil. To evaluate the accuracy of the numerical model, the present results are compared and validated against published experimental data and showed good agreement.

Numerical Analysis of Hydrofoil Dynamics by Using a Fluid-Structure Interaction Approach

2012 ◽  
Author(s):  
Tolotra Emerry Rajaomazava ◽  
Mustapha Benaouicha ◽  
Jacques-André Astolfi
Keyword(s):  
Stokes Problem ◽  
Fluid Structure Interaction ◽  
Time Discretization ◽  
Navier Stokes ◽  
Arbitrary Lagrangian Eulerian ◽  
Fluid Structure ◽  
Structure Interaction ◽  
Ale Formulation ◽  
Non Linear ◽  
Interaction Approach

In this paper, the flow over pitching and heaving hydrofoil is investigated. The viscous incompressible Navier-Stokes problem in Arbitrary Lagrangian-Eulerian (ALE) formulation is solved using the finite elements code Cast3M. The projection method is used to uncouple the velocity and pressure fields. The implicit Euler scheme is applied for time discretization of fluid equations. The dynamics of the hydrofoil is governed by a non-linear ordinary differential equation. The non-linear coupled problem is solved using the explicit staggered algorithm. The effects of fluid-structure interaction on hydrofoil dynamics and pressure center position are analyzed.

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%.

A Hybrid Numerical Model to Address Fluid Elastic Structure Interaction

2016 ◽  
Author(s):  
Manoj Kumar Gangadharan ◽  
Sriram Venkatachalam
Keyword(s):  
Numerical Model ◽  
Fluid Structure Interaction ◽  
Breaking Waves ◽  
Elastic Structure ◽  
Navier Stokes ◽  
Breaking Wave ◽  
Ocean Engineering ◽  
Fluid Structure ◽  
Strongly Coupled ◽  
Structure Interaction

Hydroelasticity is an important problem in the field of ocean engineering. It can be noted from most of the works published as well as theories proposed earlier that this particular problem was addressed based on the time independent/ frequency domain approach. In this paper, we propose a novel numerical method to address the fluid-structure interaction problem in time domain simulations. The hybrid numerical model proposed earlier for hydro-elasticity (Sriram and Ma, 2012) as well as for breaking waves (Sriram et al 2014) has been extended to study the problem of breaking wave-elastic structure interaction. The method involves strong coupling of Fully Nonlinear Potential Flow Theory (FNPT) and Navier Stokes (NS) equation using a moving overlapping zone in space and Runge kutta 2nd order with a predictor corrector scheme in time. The fluid structure interaction is achieved by a near strongly coupled partitioned procedure. The simulation was performed using Finite Element method (FEM) in the FNPT domain, Particle based method (Improved Meshless Local Petrov Galerkin based on Rankine source, IMPLG_R) in the NS domain and FEM for the structural dynamics part. The advantage of using this approach is due to high computational efficiency. The method has been applied to study the interaction between breaking waves and elastic wall.

Modal Test of Scaled-Down Reactor Internals in SMART Considering the Fluid-Structure Interaction

2011 ◽  
Author(s):  
Seungho Lim ◽  
Kyungrok Ha ◽  
Kyoung-Su Park ◽  
No-Cheol Park ◽  
Young-Pil Park ◽  
...  
Keyword(s):  
Dynamic Characteristics ◽  
Seismic Analysis ◽  
Fluid Structure Interaction ◽  
Mass Effect ◽  
Mode Shapes ◽  
Structural Dynamic ◽  
Fluid Structure ◽  
Structure Interaction ◽  
Standard Design ◽  
Reactor Internals

The System-integrated Modular Advanced ReacTor (SMART) is a small modular integral-type reactor for the seawater desalination and small-scaled power generation under development in Korea. Although the SMART is innovative reactor with a sensible mixture of the proven technology and advanced design features aimed at enhanced safety, there is no valid prototype which can specify the structural dynamic characteristics of reactor internals. Thus, extensive research for the technology verification and standard design approval are in progress. One of them is to perform the dynamic characteristics identification of reactor internals. Especially, it is focused on the added mass effect caused by the fluid-structure interaction because the reactor internals is submerged in the reactor coolant. The extracted dynamic characteristics such as the natural frequencies and the vibratory mode shapes can be used as the basis on further dynamic analysis, for example, seismic analysis and a postulated pipe break analysis.

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