scholarly journals Indicative Results and Progress on the Development of the Unified Single Solution Method for Fluid-Structure Interaction Problems

2007 ◽  
Author(s):  
C. G. Giannopapa
Keyword(s):  
Solution Method ◽  
Numerical Models ◽  
Fluid Structure Interaction ◽  
Test Case ◽  
Computational Domain ◽  
Fluid Structure ◽  
Strongly Coupled ◽  
Structure Interaction ◽  
Fully Implicit ◽  
The Difference

This paper presents the progress on the development of a novel unified solution method for solving strongly coupled fluid-structure interaction problems. The method has been developed and fully tested for solids in [1]. The new approach is based on continuum mechanics formulation for fluids and structures where both continua can be solved using the momentum and continuity equation. The difference between the two continua lies in the constitutive equations. In this framework a single set of equations is used for the simultaneous solution of both fluid and solid. The common equations are written such that velocity and pressure are unknown variables for both continua. The discretisation method used for the solution of the problems is finite volumes. The physical interface between the two continua is treated as an internal part of the computational domain and no explicit exchange of information is needed. The test case used to demonstrate the idea is wave propagation in liquid filled flexible vessels. The solution is fully implicit and transient. Results regarding pressure, velocity and wall distention at different times and various locations along the tube are presented. The method is stable and robust and can be used for the next step of development and validation against classical analytical and numerical models.

scholarly journals Linear Stability Analysis and Validation of a Unified Solution Method for Fluid-Structure-Interaction on Structural Dynamic Problems

2005 ◽  
Author(s):  
C. G. Giannopapa ◽  
G. Papadakis
Keyword(s):  
Stability Analysis ◽  
Linear Stability ◽  
Linear Stability Analysis ◽  
Solution Method ◽  
Fluid Structure Interaction ◽  
Analytic Solutions ◽  
Computational Domain ◽  
Structural Dynamic ◽  
Fluid Structure ◽  
Structure Interaction

In the conventional approach for fluid-structure interaction problems, the fluid and solid components are treated separately and information is exchanged across their interface. According to the conventional terminology, the current numerical methods can be grouped in two major categories: Partitioned methods and monolithic methods. Both methods use two separate sets of equations for fluid and solid. A unified solution method has been presented [1], which is different from these methods. The new method treats both fluid and solid as a single continuum, thus the whole computational domain is treated as one entity discretised on a single grid. Its behavior is described by a single set of equations, which are solved fully implicitly. In this paper, 2 time marching and one spatial discretisation scheme, widely used for fluids’ equations, are applied for the solution of the equations for solids. Using linear stability analysis, the accuracy and dissipation characteristics of the resulting difference equations are examined. The aforementioned schemes are applied to a transient structural problem (beam bending) and the results compare favorably with available analytic solutions and are consistent with the conclusions of the stability analysis. A parametric investigation using different meshes, time steps and beam sizes is also presented. For all cases examined the numerical solution was stable and robust and proved to be suitable for the next stage of application to full fluid-structure interaction problems.

Linear Stability Analysis and Application of a New Solution Method of the Elastodynamic Equations Suitable for a Unified Fluid-Structure-Interaction Approach

2008 ◽  
Vol 130 (3) ◽  
Author(s):  
C. G. Giannopapa ◽  
G. Papadakis
Keyword(s):  
Stability Analysis ◽  
Linear Stability ◽  
Linear Stability Analysis ◽  
Solution Method ◽  
Stokes Equations ◽  
Fluid Structure Interaction ◽  
Analytic Solutions ◽  
Computational Domain ◽  
Fluid Structure ◽  
Structure Interaction

In the conventional approach for fluid-structure-interaction problems, the fluid and solid components are treated separately and information is exchanged across their interface. According to the conventional terminology, the current numerical methods can be grouped in two major categories: partitioned methods and monolithic methods. Both methods use separate sets of equations for fluid and solid that have different unknown variables. A unified solution method has been presented in the previous work of Giannopapa and Papadakis (2004, “A New Formulation for Solids Suitable for a Unified Solution Method for Fluid-Structure Interaction Problems,” ASME PVP 2004, San Diego, CA, July, PVP Vol. 491–1, pp. 111–117), which is different from these methods. The new approach treats both fluid and solid as a single continuum; thus, the whole computational domain is treated as one entity discretized on a single grid. Its behavior is described by a single set of equations, which are solved fully implicitly. In this paper, the elastodynamic equations are reformulated so that they contain the same unknowns as the Navier–Stokes equations, namely, velocities and pressure. Two time marching and one spatial discretization scheme, widely used for fluid equations, are applied for the solution of the reformulated equations for solids. Using linear stability analysis, the accuracy and dissipation characteristics of the resulting difference equations are examined. The aforementioned schemes are applied to a transient structural problem (beam bending) and the results compare favorably with available analytic solutions and are consistent with the conclusions of the stability analysis. A parametric investigation using different meshes, time steps, and beam dimensions is also presented. For all cases examined, the numerical solution was stable and robust and therefore is suitable for the next stage of application to full fluid-structure-interaction problems.

Towards a Unified Solution Method for Fluid-Structure Interaction Problems: Progress and Challenges

2006 ◽  
Author(s):  
G. Papadakis ◽  
C. G. Giannopapa
Keyword(s):  
Stress Tensor ◽  
Solution Method ◽  
Constitutive Relations ◽  
Fluid Structure Interaction ◽  
Strain Tensor ◽  
Internal Stresses ◽  
Fluid Structure ◽  
Structure Interaction ◽  
The Difference ◽  
Fundamental Equations

The paper presents the progress in the development of a novel unified method for solving coupled fluid-structure interaction problems as well as the associated major challenges. The new approach is based on the fact that there are four fundamental equations in continuum mechanics: the continuity equation and the three momentum equations that describe Newton’s second law in three directions. These equations are valid for fluids and solids, the difference being in the constitutive relations that provide the internal stresses in the momentum equations: in solids the stress tensor is a function of the strain tensor while in fluids the viscous stress tensor depends on the rate of strain tensor. The equations are written in such a way that both media have the same unknown variables, namely the three velocity components and pressure. The same discretisation technique (finite volume) and solution method (segregated approach) are used irrespective of the medium. Also the same methodology to handle the pressure-velocity coupling is employed. A common set of variables as well as a unified discretisation and solution method leads to a strong coupling between the two media and is very beneficial for the robustness of the algorithm. Significant challenges include the derivation of consistent boundary conditions for the pressure equation in boundaries with prescribed traction as well as the handling of discontinuity of pressure at the fluid-structure interface.

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.

Composed Fluid–Structure Interaction Interface for Horizontal Axis Wind Turbine Rotor

2015 ◽  
Vol 10 (4) ◽  
Author(s):  
Dubravko Matijašević ◽  
Zdravko Terze ◽  
Milan Vrdoljak
Keyword(s):  
Wind Turbine ◽  
Numerical Models ◽  
Stress Test ◽  
Fluid Structure Interaction ◽  
Horizontal Axis ◽  
High Fidelity ◽  
Horizontal Axis Wind Turbine ◽  
Recovery Method ◽  
Fluid Structure ◽  
Structure Interaction

In this paper, we propose a technique for high-fidelity fluid–structure interaction (FSI) spatial interface reconstruction of a horizontal axis wind turbine (HAWT) rotor model composed of an elastic blade mounted on a rigid hub. The technique is aimed at enabling re-usage of existing blade finite element method (FEM) models, now with high-fidelity fluid subdomain methods relying on boundary-fitted mesh. The technique is based on the partition of unity (PU) method and it enables fluid subdomain FSI interface mesh of different components to be smoothly connected. In this paper, we use it to connect a beam FEM model to a rigid body, but the proposed technique is by no means restricted to any specific choice of numerical models for the structure components or methods of their surface recoveries. To stress-test robustness of the connection technique, we recover elastic blade surface from collinear mesh and remark on repercussions of such a choice. For the HAWT blade recovery method itself, we use generalized Hermite radial basis function interpolation (GHRBFI) which utilizes the interpolation of small rotations in addition to displacement data. Finally, for the composed structure we discuss consistent and conservative approaches to FSI spatial interface formulations.

Goal-Oriented Mesh Adaptivity for Fluid-Structure Interaction with Application to Heart-Valve Settings

2012 ◽  
Vol 59 (1) ◽  
pp. 73-99 ◽  
Author(s):  
Thomas Wick
Keyword(s):  
Heart Valve ◽  
Fluid Structure Interaction ◽  
Computational Cost ◽  
Coupling Scheme ◽  
Error Estimator ◽  
Computational Domain ◽  
Mesh Adaptivity ◽  
Fluid Structure ◽  
Structure Interaction ◽  
Mesh Adaption

Goal-Oriented Mesh Adaptivity for Fluid-Structure Interaction with Application to Heart-Valve SettingsWe apply a fluid-structure interaction method to simulate prototypical dynamics of the aortic heart-valve. Our method of choice is based on a monolithic coupling scheme for fluid-structure interactions in which the fluid equations are rewritten in the ‘arbitrary Lagrangian Eulerian’ (ALE) framework. To prevent the backflow of structure waves because of their hyperbolic nature, a damped structure equation is solved on an artificial layer that is used to prolongate the computational domain. The increased computational cost in the presence of the artificial layer is resolved by using local mesh adaption. In particular, heuristic mesh refinement techniques are compared to rigorous goal-oriented mesh adaption with the dual weighted residual (DWR) method. A version of this method is developed for stationary settings. For the nonstationary test cases the indicators are obtained by a heuristic error estimator, which has a good performance for the measurement of wall stresses. The results for prototypical problems demonstrate that heart-valve dynamics can be treated with our proposed concepts and that the DWR method performs best with respect to a certain target functional.

Computational dynamic models and experiments in the fluid–structure interaction of pipe systems

2016 ◽  
Vol 43 (1) ◽  
pp. 60-72 ◽  
Author(s):  
M. Simão ◽  
J. Mora-Rodriguez ◽  
H.M. Ramos
Keyword(s):  
Computational Models ◽  
Dynamic Models ◽  
Numerical Models ◽  
Fluid Structure Interaction ◽  
Rheological Behaviour ◽  
Pipe Material ◽  
Expansion Joints ◽  
Fluid Structure ◽  
Pipe System ◽  
Structure Interaction

Fluid–structure interaction is analyzed using 1D and 3D computational models and results from an experimental facility, where transient events are induced. The water-hammer phenomenon is modelled by a 1D model based on the method of characteristics and the COMSOL Multiphysics 4.3b, which uses finite element method to study the fluid structural interaction involved in a long pressurized pipe system with curves, expansion joints, anchor and support blocks and different rheological behaviour of the pipe material. Comparisons are made between the experimental data and the two numerical models, where the type of response of each model was enhanced, as well as the ability of each model to simulate real conditions.

Sign in / Sign up

Export Citation Format

Share Document