Dynamic Analysis of the Joined-Wing Configuration in High-Altitude Long-Endurance Aircraft Using Fluid-Structure Interaction Model

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):  
Ali Marzban ◽  
Murthy Lakshmiraju ◽  
Nigel Richardson ◽  
Mike Henneke ◽  
Guangyu Wu ◽  
...  

In this study a one-way coupled fluid-structure interaction (FSI) between ocean waves and a simplified offshore platform deck structure was modeled. The FSI model consists of a Volume of Fluid (VOF) based hydrodynamics model, a structural model and an interface to synchronize data between these two. A Computational Fluid Dynamics (CFD) analysis was used to capture the breaking wave and impact behavior of the fluid on the structure using commercially available software STAR-CCM+. A 3D Finite Element (FE) model of the platform deck developed in ABAQUS was used to determine the deflection of the structure due to hydrodynamic loads. Nonlinear material behavior was used for all structural parts in the FE model. Transient dynamic structural analysis and CFD analysis were coupled by transferring the CFD-predicted pressure distribution to the structural part in each time step using the co-simulation capabilities of STAR-CCM+ and ABAQUS. The one-way FSI model was applied to investigate the possible physical causes of observed wave damage of an offshore platform deck during a hurricane. It was demonstrated that with proper physical conditions/configurations, the FSI model could reproduce a structural deformation comparable to field measurement and provide valuable insight for forensic analysis.


2012 ◽  
Vol 468-471 ◽  
pp. 238-244
Author(s):  
Zhao Wang ◽  
Zhi Jin Zhou ◽  
Hao Lu ◽  
Ze Jun Wen ◽  
Yi Min Xia

Using finite element software ADINA, three coupling models on fluid-structure interaction among internal fluid—pipe—external fluid in the lifting pipeline were researched. Firstly, coupling finite element model on fluid structure interaction of lifting pipeline was established and the first sixth order natural frequencies and principal vibration modes were attained at different ore conveying volume concentration and cross-section size of pipeline;Then natural frequencies of three couplings were compared with two couplings and no coupling according to the above condition, and FSI effect on natural frequency of pipeline was discussed. The calculation results were shown that the natural frequency of the pipe and its relative error reduced with the volume concentration and the relative wall thickness increased, which explain the reason that has better accuracy considering three couplings than other .These results have certain directive significance on the dynamic response, structure design and study of reduction vibration of lifting pipeline.


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

Advanced composite materials such as Carbon Fiber Reinforced Plastics (CFRP) are being applied to many aircraft structures in order to improve performance and reduce weight. Most composites have strong, stiff fibers in a matrix which is weaker and less stiff. However, aircraft wings can break due to Fluid-Structure Interaction (FSI) oscillations or material fatigue. This paper focuses on the analysis of a non-linear fluid-structure interaction problem and its solution in the finite element software package DOpElib: the deal.II based optimization library. The principal aim of this research is to explore and understand the behaviour of the fluid-structure interaction during the impact of a deformable material (e.g. an aircraft wing) on air. Here we briefly describe the analysis of incompressible Navier-Stokes and Elastodynamic equations in the arbitrary Lagrangian-Eulerian (ALE) frameworks in order to numerically simulate the FSI effect on a double wedge airfoil. Since analytical solutions are only available in special cases, the equation needs to be solved by numerical methods. This coupled problem is defined in a monolithic framework and fractional-step-θ time stepping scheme are implemented. Spatial discretization is based on a Galerkin finite element scheme. The non-linear system is solved by a Newton method. The implementation using the software library package DOpElib and deal.II serves for the computation of different fluid-structure configurations.


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):  
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):  
Praveen Bhat ◽  
Satish Shenoy B ◽  
Raghuvir Pai

Conventional method of performing Elasto-hydrodynamic Lubrication (EHL) analysis on a partial arc bearing involves simplification of actual physical model and developing complex codes. This paper presents the overall EHL analysis of a radialy adjustable single 60° partial arc bearing using the sequential application of Computational Fluid Dynamics (CFD) and Computational Structural Dynamics (CSD). Here the coupled field analysis uses the capabilities of commercially available Finite Element Software ANSYS/FLOTRAN and the technique of Fluid Structure Interaction (FSI). The pressure field has been obtained using CFD considering the flow to be laminar. Stress distribution and deformation in the pad due to resulting pressure force is obtained using Finite Element Method (FEM), satisfying the boundary conditions. The stress distribution indicates the critical points in the pad. In this paper the static characteristics of radialy adjustable single 60° partial arc bearings are predicted for different eccentricity ratios and length to diameter (L/D) ratios. The results show reasonable agreement in general.


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.


2014 ◽  
Vol 1065-1069 ◽  
pp. 569-574
Author(s):  
Min Zhe Zhou ◽  
Tong Chun Li ◽  
Yuan Ding ◽  
Xiao Chun Zhou

Coupled vibration of water and stop log gate in the layered water intake structure will occur under the condition of the sudden load changes. A fluid-structure interaction (FSI) finite element model of the layered water intake structure of a hydropower station was established by using the finite element software ADINA to simulate the process of power on and off and the FSI phenomena of stop log gate during each process, and also verify the security of the scheme. The results show that fluid-structure interaction has a significant impact on the running of the layered water intake.


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