scholarly journals Fluid–Structure Interaction Simulation of Vortex-Induced Vibration of a Flexible Hydrofoil

2017 ◽  
Vol 139 (4) ◽  
Author(s):  
Abe H. Lee ◽  
Robert L. Campbell ◽  
Brent A. Craven ◽  
Stephen A. Hambric

Fluid–structure interaction (FSI) is investigated in this study for vortex-induced vibration (VIV) of a flexible, backward skewed hydrofoil. An in-house finite element structural solver finite element analysis nonlinear (FEANL) is tightly coupled with the open-source computational fluid dynamics (CFD) library openfoam to simulate the interaction of a flexible hydrofoil with vortical flow structures shed from a large upstream rigid cylinder. To simulate the turbulent flow at a moderate computational cost, hybrid Reynolds-averaged Navier–Stokes–large eddy simulation (RANS–LES) is used. Simulations are first performed to investigate key modeling aspects that include the influence of CFD mesh resolution and topology (structured versus unstructured mesh), time-step size, and turbulence model (delayed-detached-eddy-simulation and k−ω shear stress transport-scale adaptive simulation). Final FSI simulations are then performed and compared against experimental data acquired from the Penn State-ARL 12 in water tunnel at two flow conditions, 2.5 m/s and 3.0 m/s, corresponding to Reynolds numbers of 153,000 and 184,000 (based on the cylinder diameter), respectively. Comparisons of the hydrofoil tip-deflections, reaction forces, and velocity fields (contours and profiles) show reasonable agreement between the tightly coupled FSI simulations and experiments. The primary motivation of this study is to assess the capability of a tightly coupled FSI approach to model such a problem and to provide modeling guidance for future FSI simulations of rotating propellers in crashback (reverse propeller operation).

Author(s):  
Prabu Ganesh Ravindren ◽  
Kirti Ghia ◽  
Urmila Ghia

Recent studies of the joined-wing configuration of the High Altitude Long Endurance (HALE) aircraft have been performed by analyzing the aerodynamic and structural behaviors separately. In the present work, a fluid-structure interaction (FSI) analysis is performed, where the fluid pressure on the wing, and the corresponding non-linear structural deformation, are analyzed simultaneously using a finite-element matrix which couples both fluid and structural solution vectors. An unsteady, viscous flow past the high-aspect ratio wing causes it to undergo large deflections, thus changing the domain shape at each time step. The finite element software ANSYS 11.0 is used for the structural analysis and CFX 11.0 is used for the fluid analysis. The structural mesh of the semi-monocoque joined-wing consists of finite elements to model the skin panel, ribs and spars. Appropriate mass and stress distributions are applied across the joined-wing structure [Kaloyanova et al. (2005)], which has been optimized in order to reduce global and local buckling. The fluid region is meshed with very high mesh density at the fluid-structure interface and where flow separation is predicted across the joint of the wing. The FSI module uses a sequentially-coupled finite element equation, where the main coupling matrix utilizes the direction of the normal vector defined for each pair of coincident fluid and structural element faces at the interface [ANSYS 11.0 Documentation]. The k-omega turbulence model captures the fine-scale turbulence effects in the flow. An angle of attack of 12°, at a Mach number of 0.6 [Rangarajan et al. (2003)], is used in the simulation. A 1-way FSI analysis has been performed to verify the proper transfer of loads across the fluid-structure interface. The CFX pressure results on the wing were transferred across the comparatively coarser mesh on the structural surface. A maximum deflection of 16 ft is found at the wing tip with a calculated lift coefficient of 1.35. The results have been compared with the previous study and have proven to be highly accurate. This will be taken as the first step for the 2-way simulation. The effect of a coupled 2-way FSI analysis on the HALE aircraft joined wing configuration will be shown. The structural deformation history will be presented, showing the displacement of the joined-wing, along the wing span over a period of aerodynamic loading. The fluid-structure interface meshing and the convergence at each time step, based on the quantities transferred across the interface will also be discussed.


Author(s):  
Bhuiyan Shameem Mahmood Ebna Hai ◽  
Markus Bause

This contribution is the first part of three papers on Adaptive Multigrid Methods for eXtended Fluid-Structure Interaction (eXFSI) Problem, where we introduce a monolithic variational formulation and solution techniques. In a monolithic nonlinear fluid-structure interaction (FSI), the fluid and structure models are formulated in different coordinate systems. This makes the FSI setup of a common variational description difficult and challenging. This article presents the state-of-the-art of recent developments in the finite element approximation of FSI problem based on monolithic variational formulation in the well-established arbitrary Lagrangian Eulerian (ALE) framework. This research will focus on the newly developed mathematical model of a new FSI problem which is called eXtended Fluid-Structure Interaction (eXFSI) problem in ALE framework. This model is used to design an on-live Structural Health Monitoring (SHM) system in order to determine the wave propagation in moving domains and optimum locations for SHM sensors. eXFSI is strongly coupled problem of typical FSI with a wave propagation problem on the fluid-structure interface, where wave propagation problems automatically adopted the boundary conditions from of the typical FSI problem at each time step. The ALE approach provides a simple, but powerful procedure to couple fluid flows with solid deformations by a monolithic solution algorithm. In such a setting, the fluid equations are transformed to a fixed reference configuration via the ALE mapping. The goal of this work is the development of concepts for the efficient numerical solution of eXFSI problem, the analysis of various fluid-mesh motion techniques and comparison of different second-order time-stepping schemes. This work consists of the investigation of different time stepping scheme formulations for a nonlinear FSI problem coupling the acoustic/elastic wave propagation on the fluid-structure interface. Temporal discretization is based on finite differences and is formulated as an one step-θ scheme; from which we can consider the following particular cases: the implicit Euler, Crank-Nicolson, shifted Crank-Nicolson and the Fractional-Step-θ schemes. The nonlinear problem is solved with Newton’s method whereas the spatial discretization is done with a Galerkin finite element scheme. To control computational costs we apply a simplified version of a posteriori error estimation using the dual weighted residual (DWR) method. This method is used for the mesh adaptation during the computation. The implementation is accomplished via the software library package DOpElib and deal.II for the computation of different eXFSI configurations.


Author(s):  
Y. W. Kwon ◽  
J. C. Jo

A computational technique was developed for analysis of fluid-structure interaction. The fluid flow was solved using the lattice Boltzmann method which found to be computationally simple and efficient. In order to apply the lattice Boltzmann method to irregular shapes of fluid domains, the finite element based lattice Boltzmann method was developed. In addition, the turbulent model was also implemented into the lattice Boltzmann formulation. Structures were analyzed using either beam or shell elements depending of the nature of the structures. Then, coupled transient fluid flow and structural dynamics were solved one after another for each time step. Numerical examples for both 2-D and 3-D fluid-structure interaction problems were presented to demonstrate the developed techniques.


Fluids ◽  
2021 ◽  
Vol 6 (4) ◽  
pp. 149
Author(s):  
Andrea Chierici ◽  
Leonardo Chirco ◽  
Sandro Manservisi

Fluid-structure interaction (FSI) problems are of great interest, due to their applicability in science and engineering. However, the coupling between large fluid domains and small moving solid walls presents numerous numerical difficulties and, in some configurations, where the thickness of the solid wall can be neglected, one can consider membrane models, which are derived from the Koiter shell equations with a reduction of the computational cost of the algorithm. With this assumption, the FSI simulation is reduced to the fluid equations on a moving mesh together with a Robin boundary condition that is imposed on the moving solid surface. In this manuscript, we are interested in the study of inverse FSI problems that aim to achieve an objective by changing some design parameters, such as forces, boundary conditions, or geometrical domain shapes. We study the inverse FSI membrane model by using an optimal control approach that is based on Lagrange multipliers and adjoint variables. In particular, we propose a pressure boundary optimal control with the purpose to control the solid deformation by changing the pressure on a fluid boundary. We report the results of some numerical tests for two-dimensional domains to demonstrate the feasibility and robustness of our method.


2014 ◽  
Vol 91 ◽  
pp. 37-42 ◽  
Author(s):  
Alexander M. Belostosky ◽  
Pavel A. Akimov ◽  
Taymuraz B. Kaytukov ◽  
Irina N. Afanasyeva ◽  
Anton R. Usmanov ◽  
...  

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