scholarly journals Study of modal analysis based on fluid-structure interaction

2018 ◽  
Vol 11 (6) ◽  
pp. 1391-1417
Author(s):  
M. PEGORARO ◽  
F. A. A. GOMES ◽  
P. R. NOVAK
Keyword(s):  
Numerical Modeling ◽  
Fluid Flow ◽  
Modal Analysis ◽  
Fluid Structure Interaction ◽  
Small Scale ◽  
Vibration Modes ◽  
Fluid Structure ◽  
Structure Interaction ◽  
Coupled Problem ◽  
Structure Problem

Abstract In this work, a coupled fluid-structure problem is approached, comparing the result with the modal analysis of a structure. The objective of this work is to analyze the physical phenomenon of fluid-structure interaction of a flexible structure. For this, the coupled problem solved using an Arbitrary Lagrangean-Eulerian (ALE) approach. As support for solving the mathematical equations of coupled problem, ANSYS® physical analysis software was used. An experimental modal analysis, using the Rational Fractional Polynomial method was developed for a small scale steel structure, and the result of this was compared with the result obtained from the model simulated in the software. Their vibration modes and natural frequencies obtained by numerical modeling were validated experimentally. Whit the numerical modeling of the modal analysis of a structure experimentally validated, attempted to analyze the dynamic behavior of the structure when it is subjected to a load due to a fluid-flow through a coupled fluid-structure problem. The results presented in this work show that the structure subjected to loads due to the fluid-flow, moves according to its vibration modes.

scholarly journals Numerical modeling in arterial hemodynamics incorporating fluid-structure interaction and microcirculation

2021 ◽  
Vol 18 (1) ◽  
Author(s):  
Fan He ◽  
Lu Hua ◽  
Tingting Guo
Keyword(s):  
Numerical Modeling ◽  
Shear Stress ◽  
Wall Shear Stress ◽  
Fluid Structure Interaction ◽  
Rigid Wall ◽  
Fluid Structure ◽  
Structure Interaction ◽  
Arterial Hemodynamics ◽  
Wall Compliance ◽  
Wall Shear

Abstract Background The effects of arterial wall compliance on blood flow have been revealed using fluid-structure interaction in last decades. However, microcirculation is not considered in previous researches. In fact, microcirculation plays a key role in regulating blood flow. Therefore, it is very necessary to involve microcirculation in arterial hemodynamics. Objective The main purpose of the present study is to investigate how wall compliance affects the flow characteristics and to establish the comparisons of these flow variables with rigid wall when microcirculation is considered. Methods We present numerical modeling in arterial hemodynamics incorporating fluid-structure interaction and microcirculation. A novel outlet boundary condition is employed to prescribe microcirculation in an idealised model. Results The novel finding in this work is that wall compliance under the consideration of microcirculation leads to the increase of wall shear stress in contrast to rigid wall, contrary to the traditional result that wall compliance makes wall shear stress decrease when a constant or time dependent pressure is specified at an outlet. Conclusions This work provides the valuable study of hemodynamics under physiological and realistic boundary conditions and proves that wall compliance may have a positive impact on wall shear stress based on this model. This methodology in this paper could be used in real model simulations.

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.

An Investigation of the Aerodynamic and Vibration Behavior of a Helicopter Rotor Blade

2020 ◽  
Author(s):  
Mohammad Khairul Habib Pulok ◽  
Uttam K. Chakravarty
Keyword(s):  
Rotor Blade ◽  
Fluid Structure Interaction ◽  
Interaction Model ◽  
Scale Model ◽  
Helicopter Rotor ◽  
Small Scale ◽  
Fluid Structure ◽  
Structure Interaction ◽  
Aerodynamic Analysis ◽  
Helicopter Rotor Blade

Abstract Rotary-wing aircrafts are the best-suited option in many cases for its vertical take-off and landing capacity, especially in any congested area, where a fixed-wing aircraft cannot perform. Rotor aerodynamic loading is the major reason behind helicopter vibration, therefore, determining the aerodynamic loadings are important. Coupling among aerodynamics and structural dynamics is involved in rotor blade design where the unsteady aerodynamic analysis is also imperative. In this study, a Bo 105 helicopter rotor blade is considered for computational aerodynamic analysis. A fluid-structure interaction model of the rotor blade with surrounding air is considered where the finite element model of the blade is coupled with the computational fluid dynamics model of the surrounding air. Aerodynamic coefficients, velocity profiles, and pressure profiles are analyzed from the fluid-structure interaction model. The resonance frequencies and mode shapes are also obtained by the computational method. A small-scale model of the rotor blade is manufactured, and experimental analysis of similar contemplation is conducted for the validation of the numerical results. Wind tunnel and vibration testing arrangements are used for the experimental validation of the aerodynamic and vibration characteristics by the small-scale rotor blade. The computational results show that the aerodynamic properties of the rotor blade vary with the change of angle of attack and natural frequency changes with mode number.

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.

A Homogenization Method for the Modal Analysis of a Nuclear Reactor With Fluid-Structure Interaction

2006 ◽  
Author(s):  
Jean-Franc¸ois Sigrist ◽  
Daniel Broc
Keyword(s):  
Modal Analysis ◽  
Nuclear Reactor ◽  
Mass Operator ◽  
Fluid Structure Interaction ◽  
Homogenization Method ◽  
Theoretical Point ◽  
Element Discretization ◽  
Fluid Structure ◽  
Structure Interaction ◽  
Internal Structures

The present paper exposes a homogenization method developed in order to perform the modal analysis of a nuclear reactor with fluid-structure interaction effects. The homogenization approach is used in order to take into account the presence of internal structures within the pressure vessel. A homogenization method is proposed in order to perform a numerical calculation of the frequencies and modal masses for the eigenmodes of the coupled fluid-structure problem. The technique allows the use of a simplified fluid-structure model that takes into account the presence of internal structures: the theory bases are first recalled, leading to a new formulation of the fluid-structure coupled problem. The finite element discretization of the coupled formulation leads to the modification of the classical fluid-structure interaction operators. The consistency of the formulation is established from a theoretical point of view by evaluating the total mass of the coupled system with the fluid and structure mass operator, and the modified added mass operator. The method is tested and validated on a 2D case (two concentric cylinders with periodical rigid inclusions within the annular space) and applied on the industrial case. A complete modal analysis (calculation of frequencies and modal masses) is performed on a simplified geometry of a nuclear reactor with and without internal structures. Numerical results are then compared and discussed, and the influence of the internal structures on the fluid-structure coupled phenomenon is highlighted.

Modal Analysis of Fluid-Structure Interaction in a Bent Pipeline

2016 ◽  
Author(s):  
Gudrun Mikota ◽  
Rainer Haas ◽  
Evgeny Lukachev
Keyword(s):  
Modal Analysis ◽  
Degrees Of Freedom ◽  
Coupling Effect ◽  
Fluid Structure Interaction ◽  
Interaction Model ◽  
Coupling Mechanism ◽  
Fluid Structure ◽  
Structure Interaction ◽  
Resonance Coupling ◽  
Measured Frequency Response

Fluid-structure interaction in a bent pipeline is investigated by modal methods. Measured frequency response functions between flow rate excitation and pressure response indicate a coupling effect near the third pipeline resonance. Using modal coordinates for the hydraulic and the mechanical subsystems, a two-degrees-of-freedom study of resonance coupling is carried out. An experimental modal analysis of the coupled hydraulic-mechanical system confirms the predicted resonance splitting; it illustrates the coupling mechanism and shows the relevant mechanical part. An analytical fluid-structure interaction model succeeds in reproducing the measured coupling effect. This model is also used for modification prediction; it demonstrates that an appropriate assembly of mass and damping on the pipeline can help to reduce hydraulic resonance amplitudes.

scholarly journals Estimation of Loading-Driven Fluid-Flow Pattern in Lacunar-Canalicular Space Using Fluid Structure Interaction

2020 ◽  
Vol 1504 ◽  
pp. 012006
Author(s):  
Rakesh Kumar ◽  
Salil Khana ◽  
Abhishek Kumar Tiwari ◽  
Dharmendra Tripathi ◽  
Niti Nipun Sharma
Keyword(s):  
Fluid Flow ◽  
Flow Pattern ◽  
Fluid Structure Interaction ◽  
Fluid Structure ◽  
Structure Interaction
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