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The DSpace digital repository system captures, stores, indexes, preserves, and distributes digital research material.Tue, 05 Nov 2024 03:10:53 GMT2024-11-05T03:10:53ZTheoretical and numerical investigations of frequency analysis of two circular cylinders oscillating in a incompressible viscous fluid
http://hdl.handle.net/10985/10284
Theoretical and numerical investigations of frequency analysis of two circular cylinders oscillating in a incompressible viscous fluid
RAZAFIMAHERY, Fulgence; EL BAROUDI, Adil
A potential flow is presented in this paper for the analysis of the fluid-structure interaction systems including, but not limited to, the idealized human head. The model considers a cerebro-spinal fluid (CSF) medium interacting with two solid domain. The fluid field is governed by the linearized Navier–Stokes equation. A potential technique is used to obtain a general solution for a problem. The method consists in solving analytically partial differential equations obtained from the linearized Navier–Stokes equation. From the solution, modal shapes and stokes cells are shown. In the analysis, the elastic skull model and the rigid skull model are presented. A finite element analysis is also used to check the validity of the present method. The results from the proposed method are in good agreement with numerical solutions. The effects of the fluid thickness is also investigated.
Wed, 01 Jan 2014 00:00:00 GMThttp://hdl.handle.net/10985/102842014-01-01T00:00:00ZRAZAFIMAHERY, FulgenceEL BAROUDI, AdilA potential flow is presented in this paper for the analysis of the fluid-structure interaction systems including, but not limited to, the idealized human head. The model considers a cerebro-spinal fluid (CSF) medium interacting with two solid domain. The fluid field is governed by the linearized Navier–Stokes equation. A potential technique is used to obtain a general solution for a problem. The method consists in solving analytically partial differential equations obtained from the linearized Navier–Stokes equation. From the solution, modal shapes and stokes cells are shown. In the analysis, the elastic skull model and the rigid skull model are presented. A finite element analysis is also used to check the validity of the present method. The results from the proposed method are in good agreement with numerical solutions. The effects of the fluid thickness is also investigated.Fluid–structure interaction within three-dimensional models of an idealized arterial wall
http://hdl.handle.net/10985/10015
Fluid–structure interaction within three-dimensional models of an idealized arterial wall
RAZAFIMAHERY, Fulgence; RAKOTOMANANA, Lalaonirina; EL BAROUDI, Adil
The ascending branch of the aorta is one of the most stressed organ of the arterial system. We aim to design a biomechanical model for analysing the aorta dynamics under a shock. The model includes the aorta layers and the influence of the blood pressure. We undertake a three-dimensional modal analysis of the coupled aorta–blood system. We determine in the present work the coupled natural frequencies and the modes shapes of the system of the aorta and blood. Three models are presented in this study: three-layers model, two layers model and one layer model. For the analytical solving a potential technique is used to obtain a general solution for an aorta domain. The finite element model is then validated by these original analytical solutions. The results from the proposed method are in good agreement with numerical solutions.
Wed, 01 Jan 2014 00:00:00 GMThttp://hdl.handle.net/10985/100152014-01-01T00:00:00ZRAZAFIMAHERY, FulgenceRAKOTOMANANA, LalaonirinaEL BAROUDI, AdilThe ascending branch of the aorta is one of the most stressed organ of the arterial system. We aim to design a biomechanical model for analysing the aorta dynamics under a shock. The model includes the aorta layers and the influence of the blood pressure. We undertake a three-dimensional modal analysis of the coupled aorta–blood system. We determine in the present work the coupled natural frequencies and the modes shapes of the system of the aorta and blood. Three models are presented in this study: three-layers model, two layers model and one layer model. For the analytical solving a potential technique is used to obtain a general solution for an aorta domain. The finite element model is then validated by these original analytical solutions. The results from the proposed method are in good agreement with numerical solutions.Torsional Vibrations of Fluid-Filled Multilayered Transversely Isotropic Finite Circular Cylinder
http://hdl.handle.net/10985/11186
Torsional Vibrations of Fluid-Filled Multilayered Transversely Isotropic Finite Circular Cylinder
ABASSI, Wafik; RAZAFIMAHERY, Fulgence; EL BAROUDI, Adil
An analytical and numerical study for the torsional vibrations of viscous fluid-filled three-layer transversely isotropic cylinder is presented in this paper. The equations of motion of solid and fluid are respectively formulated using the constitutive equations of a transversely isotropic cylinder and the constitutive equations of a viscous fluid. The analytical solution of the frequency equation is obtained using the boundary conditions at the free surface of the solid layer and the boundary conditions at the fluid–solid interface. The frequency equation is deduced and analytically solved using the symbolic Software Mathematica. The finite element method using Comsol Multiphysics Software results are compared with present method for validation and an acceptable match between them were obtained. It is shown that the results from the proposed method are in good agreement with numerical solutions. The influence of fluid dynamic viscosity is thoroughly analyzed and the effect of the isotropic properties on the natural frequencies is also investigated.
Fri, 01 Jan 2016 00:00:00 GMThttp://hdl.handle.net/10985/111862016-01-01T00:00:00ZABASSI, WafikRAZAFIMAHERY, FulgenceEL BAROUDI, AdilAn analytical and numerical study for the torsional vibrations of viscous fluid-filled three-layer transversely isotropic cylinder is presented in this paper. The equations of motion of solid and fluid are respectively formulated using the constitutive equations of a transversely isotropic cylinder and the constitutive equations of a viscous fluid. The analytical solution of the frequency equation is obtained using the boundary conditions at the free surface of the solid layer and the boundary conditions at the fluid–solid interface. The frequency equation is deduced and analytically solved using the symbolic Software Mathematica. The finite element method using Comsol Multiphysics Software results are compared with present method for validation and an acceptable match between them were obtained. It is shown that the results from the proposed method are in good agreement with numerical solutions. The influence of fluid dynamic viscosity is thoroughly analyzed and the effect of the isotropic properties on the natural frequencies is also investigated.Vibration Analysis of Euler-Bernoulli Beams Partially Immersed in a Viscous Fluid
http://hdl.handle.net/10985/11185
Vibration Analysis of Euler-Bernoulli Beams Partially Immersed in a Viscous Fluid
ABASSI, Wafik; RAZAFIMAHERY, Fulgence; EL BAROUDI, Adil
The vibrational characteristics of a microbeam are well known to strongly depend on the fluid in which the beam is immersed. In this paper, we present a detailed theoretical study of the modal analysis of microbeams partially immersed in a viscous fluid. A fixed-free microbeamvibrating in a viscous fluid is modeled using the Euler-Bernoulli equation for the beams.The unsteady Stokes equations are solved using a Helmholtz decomposition technique in a two-dimensional plane containing the microbeams cross sections.The symbolic softwareMathematica is used in order to find the coupled vibration frequencies of beams with two portions. The frequency equation is deduced and analytically solved.The finite element method using ComsolMultiphysics software results is compared with present method for validation and an acceptable match between them was obtained. In the eigenanalysis, the frequency equation is generated by satisfying all boundary conditions. It is shown that the present formulation is an appropriate and new approach to tackle the problem with good accuracy.
Fri, 01 Jan 2016 00:00:00 GMThttp://hdl.handle.net/10985/111852016-01-01T00:00:00ZABASSI, WafikRAZAFIMAHERY, FulgenceEL BAROUDI, AdilThe vibrational characteristics of a microbeam are well known to strongly depend on the fluid in which the beam is immersed. In this paper, we present a detailed theoretical study of the modal analysis of microbeams partially immersed in a viscous fluid. A fixed-free microbeamvibrating in a viscous fluid is modeled using the Euler-Bernoulli equation for the beams.The unsteady Stokes equations are solved using a Helmholtz decomposition technique in a two-dimensional plane containing the microbeams cross sections.The symbolic softwareMathematica is used in order to find the coupled vibration frequencies of beams with two portions. The frequency equation is deduced and analytically solved.The finite element method using ComsolMultiphysics software results is compared with present method for validation and an acceptable match between them was obtained. In the eigenanalysis, the frequency equation is generated by satisfying all boundary conditions. It is shown that the present formulation is an appropriate and new approach to tackle the problem with good accuracy.Three-dimensional investigation of the stokes eigenmodes in hollow circular cylinder
http://hdl.handle.net/10985/8486
Three-dimensional investigation of the stokes eigenmodes in hollow circular cylinder
RAZAFIMAHERY, Fulgence; EL BAROUDI, Adil
This paper studies the influence of boundary conditions on a fluid medium of finite depth.We determine the frequencies and the modal shapes of the fluid.The fluid is assumed to be incompressible and viscous. A potential technique is used to obtain in three-dimensional cylindrical coordinates a general solution for a problem.The method consists in solving analytically partial differential equations obtained from the linearized Navier-Stokes equation. A finite element analysis is also used to check the validity of the present method. The results from the proposed method are in good agreement with numerical solutions. The effect of the fluid thickness on the Stokes eigenmodes is also investigated. It is found that frequencies are strongly influenced.
http://dx.doi.org/10.1155/2013/857821
Tue, 01 Jan 2013 00:00:00 GMThttp://hdl.handle.net/10985/84862013-01-01T00:00:00ZRAZAFIMAHERY, FulgenceEL BAROUDI, AdilThis paper studies the influence of boundary conditions on a fluid medium of finite depth.We determine the frequencies and the modal shapes of the fluid.The fluid is assumed to be incompressible and viscous. A potential technique is used to obtain in three-dimensional cylindrical coordinates a general solution for a problem.The method consists in solving analytically partial differential equations obtained from the linearized Navier-Stokes equation. A finite element analysis is also used to check the validity of the present method. The results from the proposed method are in good agreement with numerical solutions. The effect of the fluid thickness on the Stokes eigenmodes is also investigated. It is found that frequencies are strongly influenced.Transverse vibration analysis of Euler-Bernoulli beam carrying point masse submerged in fluid media
http://hdl.handle.net/10985/17034
Transverse vibration analysis of Euler-Bernoulli beam carrying point masse submerged in fluid media
RAZAFIMAHERY, Fulgence; EL BAROUDI, Adil
In the present paper, an analytical method is developed to investigate the effects of added mass on natural frequencies and mode shapes of Euler-Bernoulli beams carrying concentrated masse at arbitrary position submerged in a fluid media. A fixed-fixed beams carrying concentrated masse vibrating in a fluid is modeled using the Bernoulli-Euler equation for the beams and the acoustic equation for the fluid. The symbolic software Mathematica is used in order to find the coupled vibration frequencies of a beams with two portions. The frequency equation is deduced and analytically solved. The finite element method using Comsol Multiphysics software results are compared with present method for validation and an acceptable match between them were obtained. In the eigenanalysis, the frequency equation is generated by satisfying all boundary conditions. It is shown that the present formulation is an appropriate and new approach to tackle the problem with good accuracy.
Thu, 01 Jan 2015 00:00:00 GMThttp://hdl.handle.net/10985/170342015-01-01T00:00:00ZRAZAFIMAHERY, FulgenceEL BAROUDI, AdilIn the present paper, an analytical method is developed to investigate the effects of added mass on natural frequencies and mode shapes of Euler-Bernoulli beams carrying concentrated masse at arbitrary position submerged in a fluid media. A fixed-fixed beams carrying concentrated masse vibrating in a fluid is modeled using the Bernoulli-Euler equation for the beams and the acoustic equation for the fluid. The symbolic software Mathematica is used in order to find the coupled vibration frequencies of a beams with two portions. The frequency equation is deduced and analytically solved. The finite element method using Comsol Multiphysics software results are compared with present method for validation and an acceptable match between them were obtained. In the eigenanalysis, the frequency equation is generated by satisfying all boundary conditions. It is shown that the present formulation is an appropriate and new approach to tackle the problem with good accuracy.Prediction of Vibration Behavior of Micro-Circular Disks at Low Reynolds Number Regime
http://hdl.handle.net/10985/17031
Prediction of Vibration Behavior of Micro-Circular Disks at Low Reynolds Number Regime
RAZAFIMAHERY, Fulgence; EL BAROUDI, Adil
In the current study, a theoretical method is developed to predict the vibrational behavior of micro-circular disks filled with viscous fluids and numerical results are presented to validate the model. Vibrations with two outer boundary conditions, rigid and deformable vessel, are studied. The coupled governing equations of both rigid and deformable vessel vibration are solved by the analytical procedure, taking fluid–structure interaction into account. The fluid gap effect on the coupled eigenfrequencies is also considered. The frequency spectrum plots of the first several eigenfrequencies are presented in a wide range of fluid gap and elasticity ratio. The correctness of results is demonstrated using a commercial finite element software. It is shown that the obtained results through the proposed method reveal very good agreement with the numerical solution.
Mon, 01 Jan 2018 00:00:00 GMThttp://hdl.handle.net/10985/170312018-01-01T00:00:00ZRAZAFIMAHERY, FulgenceEL BAROUDI, AdilIn the current study, a theoretical method is developed to predict the vibrational behavior of micro-circular disks filled with viscous fluids and numerical results are presented to validate the model. Vibrations with two outer boundary conditions, rigid and deformable vessel, are studied. The coupled governing equations of both rigid and deformable vessel vibration are solved by the analytical procedure, taking fluid–structure interaction into account. The fluid gap effect on the coupled eigenfrequencies is also considered. The frequency spectrum plots of the first several eigenfrequencies are presented in a wide range of fluid gap and elasticity ratio. The correctness of results is demonstrated using a commercial finite element software. It is shown that the obtained results through the proposed method reveal very good agreement with the numerical solution.