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1

A fully-coupled three-dimensional fluid-structure interaction study on the externally-pressurized collapsible tube and the internal flow

Zhang Sen, Liu HaoFei

Journal of Theoretical and Applied Mechanics

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2023

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Vol. 61 nr 2

395--406

EN

We study the behavior of a collapsible tube conveying a fluid subject to external pressure that could occur in many physiological applications. The method of rotating spines is developed to enable an automatic mesh adaptation when the tube is deformed largely. We examine bifurcation diagrams when the tube is collapsed under a pressure driven condition and reveal that multiple solutions exist for a range of the Reynolds number. The stability characteristic of the system is discovered by determining stability of these solutions by the eigenvalue method for the first time, which is validated by solving a time-dependent problem of the system.

2

Analysis of high-speed angular ball bearing lubrication based on bi-directional fluid-solid coupling

Jiao Bowen, Bian Qiang, Wang Xinghong, Chunjiang Zhao, Chen Ming, Zhang Xiangyun

Archive of Mechanical Engineering

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2023

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LXX, nr 4

531--551

EN

The lubrication of angular contact ball bearings under high-speed motion con- ditions is particularly important to the working performance of rolling bearings. Combining the contact characteristics of fluid domain and solid domain, a lubrication calculation model for angular contact ball bearings is established based on the RNG 𝑘-𝜀 method. The pressure and velocity characteristics of the bearing basin under the conditions of rotational speed, number of balls and lubricant parameters are analyzed, and the lubrication conditions and dynamics of the angular contact ball bearings under different working conditions are obtained. The results show that the lubricant film pressure will rise with increasing speed and viscosity of the lubricant. The number of balls affects the pressure and velocity distribution of the flow field inside the bearing but has a small effect on the values of the characteristic parameters of the bearing flow field. The established CFD model provides a new approach to study the effect of fluid flow on bearing performance in angular contact ball bearings.

3

A two-stage model of an arteriovenous fistula maturation process

Jodko Daniel M., Obidowski Damian S., Reorowicz Piotr, Jóźwik Krzysztof

Acta of Bioengineering and Biomechanics

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2020

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Vol. 22, no. 2

139--153

EN

Purpose: An arteriovenous fistula has been a widely accepted vascular access for hemodialysis, however, a fistula maturation process is still not fully understood. In the short period of time, right after vein and artery shunting, the physical and biological changes take place mainly in the venous wall. A two-stage modeling method of arteriovenous fistula maturation process was proposed and presented. Methods: The first stage of the maturation was modeled with two-way coupled fluid structure interaction computer simulations. Whereas for the second, biological stage, a model was based on the change in the elasticity of the venous wall due to wall shear stress (WSS) modifications. Results: The relation between stress and radial and circumferential strain, based on Lame’s theory, makes possible to introduce a mathematical model defining modulus of elasticity, averaged WSS, and venous diameter as time functions. The presented model enables one to predict changes in the monitored parameters in the arteriovenous fistula taking place in the time longer than 90 days. Conclusions: We found that probably the majority of fistulas can be assessed to be mature too early, when the adequate blood flow rate is achieved but mean WSS still remains at the non-physiological level (>10 Pa).

4

Simulations of safety vales for fluid power systems

Domagała Mariusz, Momeni Hassan, Fabiś-Domagała Joanna, Filo Grzegorz, Lempa Paweł

System Safety : Human - Technical Facility - Environment

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2019

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Vol. 1, nr 1

670--677

EN

Hydraulic power systems are widely used in heavy machinery. Safety of such a systems have a major importance due to the fact that any failure may cause environmental contamination or serious injury. One of the component which protects hydraulic drive systems against excessive rising of working pressure is a safety valve which aim is to maintain pressure in the systems below acceptable level. Pressure control valves which plays important role in a hydraulic systems may have very simple or complex structure. Even in case of the simplest structure of such valve modeling is not an easy task. The new quality in designing hydraulic valves bring CFD method and FSI (Fluid Structure Interaction) methods.

5

Primary stenosis progression versus secondary stenosis formation in the left coronary bifurcation: A mechanical point of view

Jahromi Reza, Pakravan Hossein Ali, Saidi Mohammad Said, Firoozabadi Bahar

Biocybernetics and Biomedical Engineering

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2019

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Vol. 39, no. 1

188--198

EN

Biomechanical forces and hemodynamic factors influence the blood flow and the endothelial cells (ECs) morphology. These factors behave differently beyond the coronary artery stenosis. In the present study, unsteady blood flow in the left coronary artery (LCA) and its atherosclerotic bifurcating vessels, left anterior descending (LAD) and left circumflex (LCX) arteries, were numerically simulated to investigate the risk of plaque length development and secondary plaque formation in the post-stenotic areas. Using fluid–structure interaction (FSI) model, compliance of arterial wall and vessel curvature variations due to cardiac motion were considered. The arteries included plaques at the beginning of the bifurcation. Stenosis degree varied from 40% to 70% based on diameter reduction. Healthy coronary artery was also reconstructed to compare with the atherosclerotic arteries. Circumferential and longitudinal strains of ECs as well as wall shear stress (WSS) were computed in different locations downstream of the stenosis. It was concluded that the most critical regions experiencing low circumferential strain and low WSS were located proximal to the plaque throat, and the effects of these parameters intensified by stenosis degree. The results proposed that primary plaque length progression is more probable than secondary plaque formation distal to the stenosis when the stenosis degree increases.

6

Numerical approach in aeroelasticity

Sloboda O., Korba P., Hovanec M., Pila J.

Zeszyty Naukowe. Transport / Politechnika Śląska

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2016

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z. 93

115--122

EN

Aircraft wing design processes should comprise specific analyses oriented towards aeroelasticity, which is one of the essential factors determining flight envelope boundaries. For such cases, static or dynamic aeroelastic phenomena can be simulated using CFD simulation software. ANSYS software offers the fluid structure interaction (FSI) method for solving this multiphysics problem.

7

Numerical prediction of the effect of aortic Left Ventricular Assist Device outflow-graft anastomosis location

Mazzitelli R., Boyle F., Murphy E., Renzulli A., Fragomeni G.

Biocybernetics and Biomedical Engineering

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2016

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Vol. 36, no. 2

327--343

EN

A Left Ventricular Assist Device (LVAD) is used to provide haemodynamic support to patients with critical cardiac failure. As LVADs generate continuous flow to better understand the haemodynamic effects of these devices under different working conditions, and particularly in relation to possible outflow-graft anastomosis location, we performed 3D one-way-coupled fluid–structure-interaction (FSI) for three different LVAD working conditions and with the anastomosis location in the ascending aorta and in the descending aorta. The anatomical model used in this study is a patient-specific geometry reconstructed from computed tomography images and the mechanical support considered is similar to the Jarvik 2000®Heart LVAD. Endothelial cells can be influenced by wall stress generated from the blood flow in the artery, so they can produce vascular complications. For this reason, the second aim of this study is to evaluate and analyse, using different mechanical indicators, the wall shear distribution upon the luminal surface of the aorta generated by an LVAD. These numerical investigations demonstrate the utility of one-way-coupled FSI models to compare the haemodynamic conditions for the two LVAD outflow-grafts anastomosis locations and how both affect the aorta and its wall stress. Furthermore, the mechanical indicators allow the identification of wall regions at greater risk of atherosclerosis. The results of this study indicate that an LVAD outflow-graft anastomosis location in the ascending aorta is the optimal configuration.

8

CAD based interaction of wing structures and aerodynamic loads using finite element model and transonic small disturbance model

Zain R., Nurhadi I., Hadi B. H., Tjatra W.

Journal of KONES

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2013

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Vol. 20, No. 2

409--416

EN

A scheme has been developed to be utilized for solving the interaction between wing aerodynamic loads and the flexibility of wing structures under a quasi static assumption. The interaction is implemented through a link between the nodes of finite element model and the grids of transonic small disturbance model. The particular finite element responses, namely translational displacement vectors (TDV), are utilised for reconstructing the deflected wing surfaces. So in each iteration, the updated surfaces are involved as the parent for regenerating the TSD grids. The criteria of the Euclidean norm is applied for evaluating the convergency of aero-structure interaction. Catia-V5, is fully employed to manage three dimensional geometries for developing the model of wing structures, calculating grids and aerodynamic loads, as well as for reconstructing the updated wing surfaces. Numerous functions and objects of Catia are employed by conducting particular accesses via component object models using Microsoft Visual Basic.Net. A case study is excersized to demonstrate the interaction in transonic speed. The results shown that the scheme is very good in the way performing the interaction in quasi static condition. The utilization of TDV for generating the deflected wing surfaces indicates the capability of high fidelity deformations with respect to the complexity of finite element model.

9

Stabilization of a fluid structure interaction with nonlinear damping

Lasiecka I., Lu Y.

Control and Cybernetics

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2013

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Vol. 42, no. 1

155--181

EN

Asymptotic stability of finite energy solutions to a fluid-structure interaction with a static interface in a bounded domain Ω ∈ Rn, n = 2 is considered. It is shown that the undamped model subject to ”partial flatness” geometric condition on the in- terface produces solutions whose energy converges strongly to zero; while with a stress type feedback control applied on the interface of the structure, the model produces solutions whose energy is exponentially stable. An addition of a static damping on the interface produces solutions whose full norm in the phase space is exponentially stable. Without a static damping an interesting phenomenon occurs that steady state solutions (equilibria) might generate genuinely growing in time solutions. This is purely nonlinear phenomenon captured by newly developed techniques amenable to handle instability of steady state solutions arising from nonlinearity.

10

Numerical and Experimental Comparison of Combined Multilayer Protective Panels

Barnat W., Panowicz R., Niezgoda T.

Acta Mechanica et Automatica

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2012

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Vol. 6, no. 1

148-153

EN

The paper presents numerical and experimental analysis of combined multilayer protective panels. The developed structures are prospective solutions for enhancing protection of military vehicles and crucial elements of pipelines especially in places like river crossings.

11

Flutter analysis of IV standard configuration cascades, direct integration method

Rządkowski R., Kubitz L.

Mechanics and Mechanical Engineering

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2011

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Vol. 15, nr 3

333-341

EN

A three-dimensional nonlinear time-marching method and numerical analysis for aeroelastic behaviour of oscillating blade row has been presented. The approach is based on the solution of the coupled fluid-structure problem in which the aerodynamic and structural equations are integrated simultaneously in time. Thus providing the correct formulation of a coupled problem, as the interblade phase angle at which a stability (or instability) would occur, is a part of the solution.

12

Modeling of pulsating flow in a collapsible wall

Veshkina N., Zbiciński I., Obidowski D.

Inżynieria i Aparatura Chemiczna

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2010

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Nr 1

117-118

EN

The paper presents the methodology for verification of Fluid Structure Interaction (FS1) model for silicone pipe reflecting pulsating blood vessel in human body. The 3-term Yeoh model for strain energy density function was used in order to describe nonlinear behavior of siliconc material. To dctcr-:. mine the boundary conditions for CFD simulations our own experimental set-up was designed. A good agreement between simulation and experiment was achieved.

PL

W artykule przedstawiono metodę weryfikacji modelu (FSI) dla silikonowej rurki odzwierciedlającej zachowanie pulsującego naczynia krwionośnego z przepływającą wewnątrz krwią. Przy pomocy trój członowego modelu Yeoha funkcji gęstości energii naprężenia rozważono nieliniowe zachowanie materiału silikonowego. Aby uzyskać warunki brzegowe do symulacji CFD przeprowadzono badania na specjalnie do tego celu zbudowanej aparaturze. Otrzymano dobre dopasowanie danych z symulacji do eksperymentu.

13

Fluid-structured interaction in the case of two independent cylinders in vortex induced vibrations (VIV)

Herfjord K., Olsen G., Kvamsdal T., Okstad K. M.

International Journal of Applied Mechanics and Engineering

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2002

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Vol. 7, no 1

65-83

EN

A methodology for computing vortex-induced vibrations (VIV) on risers is presented. It is based on computation of the flow by a Computational Fluid Dynamics (CFD) program, structural dynamics by a nonlinear Computational Structural Dynamics (CSD) code and a coupling between them. Herein, we discuss in particular procedures for computing the mesh movement in staggered FSl-simulations. A two-level mesh movement procedure earlier presented for block structured meshes is enhanced for use with completely unstructured meshes. A challenging example involving VIV of two cylinders with large relative motions is presented.