scholarly journals Assessment results of fluid-structure interaction numerical simulation using fuzzy logic

2016 ◽  
Vol 20 (suppl. 1) ◽  
pp. 235-250 ◽  
Author(s):  
Zoran Markovic ◽  
Slobodan Stupar ◽  
Mirko Dinulovic ◽  
Ognjen Pekovic ◽  
Predrag Stefanovic ◽  
...  
Keyword(s):  
Fuzzy Logic ◽  
Pressure Drop ◽  
Channel Wall ◽  
Stokes Equations ◽  
Fluid Structure Interaction ◽  
Fluid Structure ◽  
Inlet Velocity ◽  
Structure Interaction ◽  
Numerical Tests ◽  
Backward Euler

A fuzzy approximation concept is applied in order to predict results of coupled computational structure mechanics and computational fluid dynamics while solving a problem of steady incompressible gas flow through thermally loaded rectangular thin-walled channel. Channel wall deforms into wave - type shapes depending on thermal load and fluid inlet velocity inducing the changes of fluid flow accordingly. A set of fluid - structure interaction (FSI) numerical tests have been defined by varying the values of fluid inlet velocity, temperature of inner and outer surface of the channel wall and numerical grid density. The unsteady Navier-Stokes equations are numerically solved using an element-based finite volume method and second order backward Euler discretization scheme. The structural model is solved by finite element method including geometric and material nonlinearities. The implicit two-way iterative code coupling, partitioned solution approach, were used while solving these numerical tests. Results of numerical analysis indicate that gravity and pressure distribution inside the channel contributes to triggering the shape of deformation. In the inverse problem, the results of FSI numerical simulations formed a database of input variables for development fuzzy logic based models considering downstream pressure drop and maximum stresses as the objective functions. Developed fuzzy models predicted targeting results within a reasonable accuracy limit at lower computation cost compared to series of FSI numerical calculations. Smaller relative difference were obtained when calculating the values of pressure drop then maximal stresses indicating that transfer function influence on output values have to be additionally investigated.

Fluid–Structure Interaction of High Aspect-Ratio Hair-Like Micro-Structures Through Dimensional Transformation Using Lattice Boltzmann Method

2016 ◽  
Vol 08 (08) ◽  
pp. 1650095 ◽  
Author(s):  
H. Devaraj ◽  
Kean C. Aw ◽  
E. Haemmerle ◽  
R. Sharma
Keyword(s):  
Fluid Flow ◽  
Drag Force ◽  
Lattice Boltzmann ◽  
Stokes Equations ◽  
Fluid Structure Interaction ◽  
Structural Response ◽  
Momentum Exchange ◽  
Fluid Structure ◽  
Structure Interaction ◽  
Micro Structures

3D printed hair-like micro-structures have been previously demonstrated in a novel micro-fluidic flow sensor aimed at sensing air flows down to rates of a few milliliters per second. However, there is a lack of in-depth understanding of the structural response of these ‘micro-hairs' under a fluid flow field. This paper demonstrates the use of lattice Boltzmann methods (LBM) to understand this structural response towards a better optimization of the micro-hair flow sensors designed to suit the end applications' needs. The LBM approach was chosen as an efficient alternative to simulate Navier–Stokes equations for modeling fluid flow around complex geometries primarily for improved accuracy and simplicity with lesser computational costs. As the spatial dimensions of the sensor's flow channel are much larger in comparison to the actual micro-hairs (the sensing element), a multidimensional approach of combining two-dimensional (D2Q9) and three-dimensional (D3Q19) lattice configurations were implemented for improved computational speeds and efficiency. The drag force on the micro-hairs was estimated using the momentum-exchange method in the D3Q19 configuration and this drag force is transferred to the structural analysis model which determines the micro-hair deformation using Euler–Bernoulli beam theory. The entirety of the LBM Fluid–Structure Interaction (FSI) model was implemented within MATLAB and the obtained results are compared against the numerical model implemented on a commercially available software package.

Fluid-Structure Interaction Approach for Numerical Investigation of a Flexible Hydrofoil Deformations in Turbulent Fluid Flow

2018 ◽  
Author(s):  
M. Benaouicha ◽  
S. Guillou ◽  
A. Santa Cruz ◽  
H. Trigui
Keyword(s):  
Fluid Flow ◽  
Numerical Model ◽  
Stokes Equations ◽  
Fluid Structure Interaction ◽  
Time Step ◽  
Fluid Structure ◽  
Turbulent Fluid Flow ◽  
Turbulent Fluid ◽  
Structure Interaction ◽  
Ale Formulation

The study deals with a 3D Fluid-Structure Interaction (FSI) numerical model of a rectangular cantilevered flexible hydrofoil subjected to a turbulent fluid flow regime. The structural response and dynamic deformations are studied by analyzing the oscillations frequencies and amplitudes, under a hydrodynamics loads. The obtained numerical results are confronted with experimental ones, for validation. The numerical model is performed in the same geometric, physical and material conditions as the experimental set-up carried out in a hydrodynamic tunnel. A polyacetal (POM) flexible hydrofoil NACA0015 with an angle of attack of 8° is considered to be immersed in a fluid flow at a Reynold number of 3 × 105. The structure is initially at rest and then moved by the action of the fluid flow. The numerical model is based on a strong coupling procedure for solving the Fluid-Structure Interaction problem. The Arbitrary Lagrangian-Eulerian (ALE) formulation of the Navier-Stokes equations is used and an anisotropic diffusion equation is solved to compute the fluid mesh velocity and position at each time step. The finite volume method is used for the numerical resolution of the fluid dynamics equations. The structure deformations are described by the linear elasticity equation which is solved by the finite elements method. The Fluid-Structure coupled problem is solved by using the partitioned FSI implicit algorithm. A good agreement between numerical and experimental results for the hydrodynamics coefficients and hydrofoil deformations, maximum deflection and frequencies is obtained. The added mass and damping are analyzed and then the FSI effect on the dynamic deformations of the structure is highlighted.

Hydraulic manifold design via additive manufacturing optimized with CFD and fluid-structure interaction simulations

2019 ◽  
Vol 25 (9) ◽  
pp. 1516-1524 ◽  
Author(s):  
Aiman A. Alshare ◽  
Fedrico Calzone ◽  
Maurizio Muzzupappa
Keyword(s):  
Additive Manufacturing ◽  
Pressure Drop ◽  
Average Velocity ◽  
A Priori ◽  
Fluid Structure Interaction ◽  
Iterative Refinement ◽  
Hydraulic Actuator ◽  
Fluid Structure ◽  
Content Type ◽  
Structure Interaction

Purpose The purpose of this study is to investigate the feasibility of using additive manufacturing (AM) technique to produce an efficient valve manifold for hydraulic actuator by redesigning valve blocks produced by conventional methods. Design/methodology/approach A priori, a computational fluid dynamics (CFD) analysis was carried out using the software ANSYS Fluent to determine the optimal flow path that results in least pressure drop, highest average velocity and least energy losses. Fluid–structure interaction (FSI) simulations, processed with imported pressure distribution from the CFD, were conducted to determine the resulting loading and deformations of the manifold assembly. Findings The new design offers a 23 per cent reduction of oil volume in the circuit, while weighing 84 per cent less. When using the new design, a decrease of pressure drop by nearly 25 per cent and an increase in the average velocity by 2.5 per cent is achieved. A good agreement, within 16 per cent, is found in terms of the pressure drop between the experiment and computational model. Originality/value It is possible to build an efficient hydraulic manifold design by iterative refinement for adequate production via selective laser melting (SLM) and minimize used material to circumventing building support structures in non-machinable features of the manifold.

Scalability study of an implicit solver for coupled fluid-structure interaction problems on unstructured meshes in 3D

2016 ◽  
Vol 32 (2) ◽  
pp. 207-219 ◽  
Author(s):  
Fande Kong ◽  
Xiao-Chuan Cai
Keyword(s):  
Stokes Equations ◽  
Fluid Structure Interaction ◽  
Three Dimensional ◽  
Coupled System ◽  
Fluid Structure ◽  
Structure Interaction ◽  
Krylov Method ◽  
Fine Mesh ◽  
Processor Cores ◽  
Fully Coupled

Fluid-structure interaction (FSI) problems are computationally very challenging. In this paper we consider the monolithic approach for solving the fully coupled FSI problem. Most existing techniques, such as multigrid methods, do not work well for the coupled system since the system consists of elliptic, parabolic and hyperbolic components all together. Other approaches based on direct solvers do not scale to large numbers of processors. In this paper, we introduce a multilevel unstructured mesh Schwarz preconditioned Newton–Krylov method for the implicitly discretized, fully coupled system of partial differential equations consisting of incompressible Navier–Stokes equations for the fluid flows and the linear elasticity equation for the structure. Several meshes are required to make the solution algorithm scalable. This includes a fine mesh to guarantee the solution accuracy, and a few isogeometric coarse meshes to speed up the convergence. Special attention is paid when constructing and partitioning the preconditioning meshes so that the communication cost is minimized when the number of processor cores is large. We show numerically that the proposed algorithm is highly scalable in terms of the number of iterations and the total compute time on a supercomputer with more than 10,000 processor cores for monolithically coupled three-dimensional FSI problems with hundreds of millions of unknowns.

scholarly journals FSI in Wind Turbines: A Review

2020 ◽  
Vol 8 (3) ◽  
pp. 37
Author(s):  
Yogesh Ramesh Patel
Keyword(s):  
Wind Turbine ◽  
Wind Turbines ◽  
Stokes Equations ◽  
Turbine Blades ◽  
Fluid Structure Interaction ◽  
Arbitrary Lagrangian Eulerian ◽  
Wind Turbine Blades ◽  
Fluid Structure ◽  
Structure Interaction ◽  
Deformable Structure

This paper provides a brief overview of the research in the field of Fluid-structure interaction in Wind Turbines. Fluid-Structure Interaction (FSI) is the interplay of some movable or deformable structure with an internal or surrounding fluid flow. Flow brought about vibrations of two airfoils used in wind turbine blades are investigated by using a strong coupled fluid shape interplay approach. The approach is based totally on a regularly occurring Computational Fluid Dynamics (CFD) code that solves the Navier-Stokes equations defined in Arbitrary Lagrangian-Eulerian (ALE) coordinates by way of a finite extent method. The need for the FSI in the wind Turbine system is studied and comprehensively presented.

scholarly journals Three-Dimensional Simulation of Fluid–Structure Interaction Problems Using Monolithic Semi-Implicit Algorithm

Fluids ◽  
2019 ◽  
Vol 4 (2) ◽  
pp. 94 ◽  
Author(s):  
Cornel Marius Murea
Keyword(s):  
Stokes Equations ◽  
Fluid Structure Interaction ◽  
Three Dimensional ◽  
Navier Stokes ◽  
Arbitrary Lagrangian Eulerian ◽  
Time Step ◽  
Fluid Structure ◽  
Structure Interaction ◽  
Dimensional Simulation ◽  
Updated Lagrangian

A monolithic semi-implicit method is presented for three-dimensional simulation of fluid–structure interaction problems. The updated Lagrangian framework is used for the structure modeled by linear elasticity equation and, for the fluid governed by the Navier–Stokes equations, we employ the Arbitrary Lagrangian Eulerian method. We use a global mesh for the fluid–structure domain where the fluid–structure interface is an interior boundary. The continuity of velocity at the interface is automatically satisfied by using globally continuous finite element for the velocity in the fluid–structure mesh. The method is fast because we solve only a linear system at each time step. Three-dimensional numerical tests are presented.

Experimental and Numerical Analysis for Fluid-Structure Interaction for an Enclosed Hexagonal Assembly

2014 ◽  
Author(s):  
Lucia Sargentini ◽  
Benjamin Cariteau ◽  
Morena Angelucci
Keyword(s):  
Numerical Method ◽  
Stokes Equations ◽  
Interaction Analysis ◽  
Flow Behavior ◽  
Fluid Structure Interaction ◽  
Water Injection ◽  
Free Vibrations ◽  
Navier Stokes ◽  
Fluid Structure ◽  
Structure Interaction

This paper is related to fluid-structure interaction analysis of sodium cooled fast reactors core (Na-FBR). Sudden liquid evacuation between assemblies could lead to overall core movements (flowering and compaction) causing variations of core reactivity. The comprehension of the structure behavior during the evacuation could improve the knowledge about some SCRAMs for negative reactivity occurred in PHÉNIX reactor and could contribute on the study of the dynamic behavior of a FBR core. An experimental facility (PISE-2c) is designed composed by a Poly-methyl methacrylate hexagonal rods (2D-plan similitude with PHÉNIX assembly) with a very thin gap between assemblies. Another experimental device (PISE-1a) is designed and composed by a single hexagonal rod for testing the dynamic characteristics. Different experiments are envisaged: free vibrations and oscillations during water injection. A phenomenological analysis is reported showing the flow behavior in the gap and the structure response. Also computational simulations are presented in this paper. An efficient numerical method is used to solve Navier-Stokes equations coupled with structure dynamic equation. The numerical method is verified by the comparison of analytic models and experiments.

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.

On a Partitioned Strong Coupling Algorithm for Modeling Fluid–Structure Interaction

2015 ◽  
Vol 07 (02) ◽  
pp. 1550021 ◽  
Author(s):  
Tao He
Keyword(s):  
Finite Element ◽  
Strong Coupling ◽  
Bluff Body ◽  
Stokes Equations ◽  
Fluid Structure Interaction ◽  
Structural Equations ◽  
Mass Source ◽  
Fluid Structure ◽  
Structure Interaction ◽  
Coupling Algorithm

This paper presents a partitioned strong coupling algorithm for fluid–structure interaction in the arbitrary Lagrangian–Eulerian finite element framework. The incompressible Navier–Stokes equations are solved by the semi-implicit characteristic-based split (CBS) scheme while the structural equations are temporally advanced by the Bathe method. The celled-based smoothed finite element method is adopted for the solution of a geometrically nonlinear solid. To update the dynamic mesh, the moving submesh approach is performed in conjunction with the ortho-semi-torsional spring analogy method. A mass source term is implanted into the pressure Poisson equation to respect the geometric conservation law for the fractional-step-type CBS fluid solver. The iterative solution is achieved by fixed-point method with Aitken's Δ2 accelerator. The proposed methodology is validated against flow-induced oscillations of a bluff body and a flexible body. The overall numerical results agree well with the available data. Some important flow phenomena have been disclosed successfully.

scholarly journals Fluid-Structure Interaction Modeling of Abdominal Aortic Aneurysms: The Impact of Patient-Specific Inflow Conditions and Fluid/Solid Coupling

2013 ◽  
Vol 135 (8) ◽  
Author(s):  
Santanu Chandra ◽  
Samarth S. Raut ◽  
Anirban Jana ◽  
Robert W. Biederman ◽  
Mark Doyle ◽  
...  
Keyword(s):  
Velocity Profile ◽  
Boundary Conditions ◽  
Fluid Structure Interaction ◽  
Aortic Aneurysms ◽  
Patient Specific ◽  
Fluid Structure ◽  
Inlet Velocity ◽  
Structure Interaction ◽  
Biomechanical Assessment ◽  
Fully Coupled

Rupture risk assessment of abdominal aortic aneurysms (AAA) by means of biomechanical analysis is a viable alternative to the traditional clinical practice of using a critical diameter for recommending elective repair. However, an accurate prediction of biomechanical parameters, such as mechanical stress, strain, and shear stress, is possible if the AAA models and boundary conditions are truly patient specific. In this work, we present a complete fluid-structure interaction (FSI) framework for patient-specific AAA passive mechanics assessment that utilizes individualized inflow and outflow boundary conditions. The purpose of the study is two-fold: (1) to develop a novel semiautomated methodology that derives velocity components from phase-contrast magnetic resonance images (PC-MRI) in the infrarenal aorta and successfully apply it as an inflow boundary condition for a patient-specific fully coupled FSI analysis and (2) to apply a one-way–coupled FSI analysis and test its efficiency compared to transient computational solid stress and fully coupled FSI analyses for the estimation of AAA biomechanical parameters. For a fully coupled FSI simulation, our results indicate that an inlet velocity profile modeled with three patient-specific velocity components and a velocity profile modeled with only the axial velocity component yield nearly identical maximum principal stress (σ1), maximum principal strain (ε1), and wall shear stress (WSS) distributions. An inlet Womersley velocity profile leads to a 5% difference in peak σ1, 3% in peak ε1, and 14% in peak WSS compared to the three-component inlet velocity profile in the fully coupled FSI analysis. The peak wall stress and strain were found to be in phase with the systolic inlet flow rate, therefore indicating the necessity to capture the patient-specific hemodynamics by means of FSI modeling. The proposed one-way–coupled FSI approach showed potential for reasonably accurate biomechanical assessment with less computational effort, leading to differences in peak σ1, ε1, and WSS of 14%, 4%, and 18%, respectively, compared to the axial component inlet velocity profile in the fully coupled FSI analysis. The transient computational solid stress approach yielded significantly higher differences in these parameters and is not recommended for accurate assessment of AAA wall passive mechanics. This work demonstrates the influence of the flow dynamics resulting from patient-specific inflow boundary conditions on AAA biomechanical assessment and describes methods to evaluate it through fully coupled and one-way–coupled fluid-structure interaction analysis.

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