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1

A numerical approach in applying panel method for the added mass of a group of sections in fluids

Zhang D., Li P., Wang Q., Yang Y.

Archives of Mechanics

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2023

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Vol. 75, nr 1-2

151--168

EN

This paper firstly expands an efficient numerical methodology developed from the source panel method to the added mass calculation of long column systems in fluid. Structures submerged in fluid are considered as two-dimensional and are discretized into a number of source panels. The influence coefficient matrices and the potential function are then calculated and the fluid forces are calculated by the unsteady Bernoulli equation. Finally, we utilize this present method to calculate the mass coefficients of some typical problems, which effectively verifies its feasibility and accuracy. This method takes into account both applicability and computational efficiency. On the one hand, in contrast to the analytical method which is only applicable to specific cross-sections, this method is applicable to arbitrary boundaries with C0 continuity in mathematics. On the other hand, this method requires less mesh and computation than commercial software. This paper extends the application of the source panel method which is widely used in aerodynamics to provide a reference for added mass calculation problems in engineering.

2

Free vibrations of Kirchhoff plates considering plate variable thickness and interaction with water including water boundaries

Lenartowicz Agnieszka, Guminiak Michał, Przychodzki Maciej

Vibrations in Physical Systems

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2021

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Vol. 32, nr 2

art. no. 2021208

EN

The natural vibrations of thin (Kirchhoff-Love) plates with constant and variable thickness and interaction with water are considered in the paper. The influence of the water free surface on natural frequencies of the coupled water-plate system is analysed too. The Finite Element Method (FEM) and the Finite Difference Method (FDM) are used to describe structural deformation and the Boundary Element Method (BEM) is applied to describe the dynamic interaction of water on a plate surface. The plate inertia forces are expressed by diagonal or consistent mass matrix. The water inertia forces are described by fully-populated mass matrix which is obtained directly from the theory of double layer potential.

3

Modelling the shock absorber piston valve using 2-way fluid-structure interaction

Buczkowski Daniel, Nowak Grzegorz

Transport Problems

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2021

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T. 16, z. 4

45--57

EN

The aim of this study is to examine the strongly coupled Fluid-Structure Interaction approach as a comprehensive method of predicting the performance of the shock absorber piston valve. For this purpose, numerical simulation sand experimental testing are carried out. The coupled CFD-FEA numerical model described in this article, contrary to the attempts made so far, takes into account the influence of contact between valve discs and the initial conditions of the disc stack preload. The model is based on the actual valve geometry used in the shock absorber design. As a result, the described approach is intended for use in industrial applications in development works, in particular, at the conceptual stage. To prove the reliability of the model, two valve compositions are chosen to be measured on a test bench and modelled in FSI simulations. For both of them, a satisfactory level of correlation is achieved, with the correlation error below 10% and well-predicted valve opening points. As a result, it is proved that the 2-way FSI approach has great potential to be successfully used to investigate the damper valve operation.

4

Numerical analysis of the effect of flexibilityon the propulsive performance of a heaving hydrofoil undergoing sinusoidal and non-sinusoidal motions

Li Fengkun, Yu Pengyao, Wang Qiang, Li Guangzhao, Wu Xiangcheng

Polish Maritime Research

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2021

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nr 4

4--19

EN

Numerical simulations of fluid‒structure interaction (FSI) on an elastic foil heaving with constant amplitude in freestream flow are carried out at a low Reynolds number of 20,000. The commercial software STAR-CCM+ is employed to solve the flow field and the large-scale passive deformation of the structure. The results show that introducing a certain degree of flexibility significantly improves the thrust and efficiency of the foil. For each Strouhal number St considered, an optimal flexibility exists for thrust; however, the propulsive efficiency keeps increasing with the increase in flexibility. The visualisation of the vorticity fields elucidates the improvement of the propulsive characteristics by flexibility. Furthermore, the mechanism of thrust generation is discussed by comparing the time-varying thrust coefficient and vortex structure in the wake for both rigid and elastic foils. Finally, in addition to sinusoidal motions, we also consider the effect of non-sinusoidal trajectories defined by flattening parameter S on the propulsive characteristics for both rigid and elastic foils. The non-sinusoidal trajectories defined by S=2 are associated with the maximum thrust, and the highest values of propulsive efficiency are obtained with S=0.5 among the cases considered in this work.

5

Vibration of simply supported plates in contact with liquid by using membrane curvilinear elements

Sygulski Ryszard

Vibrations in Physical Systems

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2020

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Vol. 31, nr 3

art. no. 2020323

EN

This paper concerns the free vibrations of a simply supported plate in contact with liquid on one side. The plate is placed into a hole of an infinite rigid wall. The analysed problem is a coupled problem of the fluid-structure type. It is assumed that the fluid is inviscid and incompressible. The boundary integral equation is used for describing the hydrodynamic pressure. The plate equation is formulated in the form of two harmonic equations. The surface of the plate is discretized using triangular curvilinear 6-node elements of the membrane type. These elements are simultaneously the finite elements for the plate and the boundary elements for the liquid. Numerical examples of the free vibrations of circular and rectangular plates are considered and are compared with analytical and analytical-numerical solutions.

6

The vibrations induced by fluid flow in plates with different Poisson’s ratios

Burlaga Bartłomiej, Stręk Tomasz

Vibrations in Physical Systems

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2020

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Vol. 31, nr 3

art. no. 2020301

EN

A fluid interacts with every solid object that is submerged in its flow. In this paper, the dynamic instability of elastic solid is modeled and analyzed based on the benchmark model. It is caused by a continuous stream of vortices (known as von Kármán vortex street). In the presented approach, prerequisites are calculated to meet the necessary conditions for this phenomenon to occur. The main objective of this study is to determine the influence of different Poisson ratios on the intensity of a solid body’s deflection. In the first part, governing equations are presented. The following part describes the model domain as well as assumed parameters with chosen values explanation. The third part presents simulation specific information - mesh and applied options. The conclusion and possible real-life applications are preceded by obtained results.

7

Numerical simulations of the flows past rotating geometries

Simon Jakub, Stankiewicz Witold

Vibrations in Physical Systems

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2020

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Vol. 31, nr 3

art. no. 2020318

EN

In the present paper the numerical approach for the modeling of the flow past rotating geometries is presented. Practical methods for two cases are described: the one where whole domain is moving with uniform angular velocity, where the rotation might be included in the governing equations only (in the terms related to Coriolis and centrifugal forces), and the one where part of the domain is rotating, whereas another one is stationary. The second case is illustrated by examples describing the steady and transient flow around a rotating propeller and by a centrifugal pump. Simulations are performed using OpenFOAM CFD solver, with the models covering flow rotation: MRF (multiple reference frame) and AMI (arbitrary mesh interface).

8

Dynamic analysis of the aortic valve functioning

Patralski Krzysztof

Journal of Theoretical and Applied Mechanics

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2020

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Vol. 58 nr 4

853--869

EN

The aim of the paper was to recognize the influence of mechanical factors on the movement of the leaflets. Mechanical stimuli may have a positive effect on remodeling the leaflet material to adapt its structure to a changing load. A model of the valve functioning process was developed. A geometric model similar to the construction of a natural valve was adopted. The hybrid process of the liquid-solid interaction problem was described. The interaction process was modeled. The problem was formulated with the Galerkin FEM method. Numerical analyses of a single valve work cycle and the calcification process of aortic valve bioprostheses were performed.

9

Numerical investigation of the basilar membrane vibration induced by the unsteady fluid flow in the human inner ear

Wahl Philipp, Ziegler Pascal, Eberhard Peter

Archive of Mechanical Engineering

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2020

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LXVII, nr 4

381--414

EN

For a deeper understanding of the inner ear dynamics, a Finite-Element model of the human cochlea is developed. To describe the unsteady, viscous creeping flow of the liquid, a pressure-displacement-based Finite-Element formulation is used. This allows one to efficiently compute the basilar membrane vibrations resulting from the fluid-structure interaction leading to hearing nerve stimulation. The results show the formation of a traveling wave on the basilar membrane propagating with decreasing velocity towards the peaking at a frequency dependent position. This tonotopic behavior allows the brain to distinguish between sounds of different frequencies. Additionally, not only the middle ear, but also the transfer behavior of the cochlea contributes to the frequency dependence of the auditory threshold. Furthermore, the fluid velocity and pressure fields show the effect of viscous damping forces and allow us to deeper understand the formation of the pressure difference, responsible to excite the basilar membrane.

10

Application of the optimization methods to the search of marine propulsion shafting global equilibrium in running condition

Ursolov Aleksandr, Batrak Yuriy, Tarelko Wieslaw

Polish Maritime Research

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2019

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nr 3

172--180

EN

Full- film hydrodynamic lubrication of marine propulsion shafting journal bearings in running condition is discussed. Considerable computational difficulties in non-linear determining the quasi-static equilibrium of the shafting are highlighted. To overcome this problem the approach using two optimization methods (the particle swarm method and the interior point method) in combination with the specially developed relaxation technique is proposed. The developed algorithm allows to calculate marine propulsion shafting bending with taking into account lubrication in all journal bearings and exact form of journal inside bearings, compared to results of most of the publications which consider lubrication only in the aft most stern tube bearing and assume rest of bearings to be represented by points. The calculation results of typical shafting design with four bearings are provided. The significance of taking into account lubrication in all bearings is shown, specifically more exact values of bearings’ reactions, shafting deflections, minimum film thickness and maximum hydrodynamic pressure in the stern tube bearing in case of considering lubrication in all bearings.

11

Study on striking ship with loading impact on the performance of the double hull oil tanker collision

Wu W., Yang Y., Zhang J., Lu J.

Polish Maritime Research

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2018

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S 2

42--48

EN

Due to the great danger of the collision of oil tankers, lots of research on the collision of oil tankers has been carried out. But, at present, the research on the collision of oil tankers mainly focuses on the loading condition of the struck ship, ignores the impact on the loading condition of the striking ship. However, during the actual oil tanker collision, the striking ship is generally in the state of loading. Therefore, it is necessary to carry out the analysis of the impact of the loading condition of the striking ship on the collision damage of the oil tanker. In this paper, the effect of striking ship with loading on the impact performance of the side structure during the collision of the cargo double hull oil tanker has been investigated. The ship collision model was established by using the finite element software ANSYS/ LS-DYNA which is based on 7000 tons of double hull oil tankers. Based on the analysis of the collision force, impact of striking speed changes, impact of striking deep changes and structural energy absorption during the collision process, the influence of the striking ship with loading on the damage mechanism and the impact performance of the double shell oil ship side structure was expounded. The results show that the influence of the striking ship with loading can be great to the damage to side hull during the research of the collision performance of the oil tanker.

12

Soil-structure-fluid interaction of the rectangular tank - seismic analysis

Kotrasová K.

Zeszyty Naukowe Politechniki Częstochowskiej. Budownictwo

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2017

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Z. 23 (173)

147-156

EN

Ground-supported tanks are used to store a variety of liquids. The fluid develops hydrodynamic pressure on walls and bottom of tank during an earthquake. This paper provides theoretical background for specification of impulsive and convective actions of fluid in liquid storage rectangular container by using analytical methods. Numerical model of tank seismic response - the endlessly long shipping channel was obtained by using of Finite Element Method (FEM), Arbitrary-Lagrangian-Eulerian (ALE), Fluid Structure Interactions (FSI) formulation in software ADINA. The results of the analytical methods and the numerical solution were compared for partially water filled channel grounded on hard soil or sub-soil 30 MNm-3. It was considered the horizontal ground motion of the earthquake in Loma Prieta.

PL

Zbiorniki naziemne są używane do przechowywania różnych płynów. Obecność płynu powoduje powstawanie ciśnienia hydrodynamicznego na ścianach i dnie zbiornika podczas trzęsienia ziemi. W artykule przedstawiono teoretyczne podstawy przy użyciu metod analitycznych dla określenia działań impulsywnych i konwekcyjnych płynu w prostokątnym pojemniku do magazynowania cieczy. Numeryczny model reakcji sejsmicznej zbiornika - nieskończenie długi kanał uzyskano, stosując metodę elementów skończonych (MES), równania Eulera-Lagrange’a, interakcję pomiędzy płynem i konstrukcją (FSI) w oprogramowaniu ADINA. Wyniki metod analitycznych i rozwiązania numerycznego porównano dla kanału częściowo wypełnionego wodą, uziemionego na twardej glebie lub podłożu 30 MNm-3. Analizowano ruch poziomy w trzęsieniu ziemi w Loma Prieta.

13

Water-exit process modeling and added-mass calculation of the submarine-launched missile

Yang J., Feng J., Li Y., Liu A., Hu J., Ma Z.

Polish Maritime Research

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2017

|

S 3

152--164

EN

In the process that the submarine-launched missile exits the water, there is the complex fluid solid coupling phenomenon. Therefore, it is difficult to establish the accurate water-exit dynamic model. In the paper, according to the characteristics of the water-exit motion, based on the traditional method of added mass, considering the added mass changing rate, the water-exit dynamic model is established. And with help of the CFX fluid simulation software, a new calculation method of the added mass that is suit for submarine-launched missile is proposed, which can effectively solve the problem of fluid solid coupling in modeling process. Then by the new calculation method, the change law of the added mass in water-exit process of the missile is obtained. In simulated analysis, for the water-exit process of the missile, by comparing the results of the numerical simulation and the calculation of theoretical model, the effectiveness of the new added mass calculation method and the accuracy of the water-exit dynamic model that considers the added mass changing rate are verified.

14

New biomimetic approach to the aircraft wing structural design based on aeroelastic analysis

Gawel D., Nowak M., Hausa H., Roszak R.

Bulletin of the Polish Academy of Sciences. Technical Sciences

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2017

|

Vol. 65, nr 5

741--750

EN

This paper presents a new biomimetic approach to the structural design. For the purpose of aircraft wing design the numerical environment combining simultaneous structural size, shape, and topology optimization based on aeroelastic analysis was developed. For the design of aircraft elements the optimization process must be treated as a multi-load case task, because during the fluid structure interaction analysis each step represents a different structural load case. Also, considering different angles of attack, during the CFD computation each result is considered. The method-specific features (such as domain independence, functional configurations during the process of optimization, and multiple load case solution implemented in the optimization scenario) enable the optimal structural form. To illustrate the algorithm functionality, the problem of determining the optimal internal wing structure was presented. The optimal internal wing structure resulting from aeroelastic computation with different angles of attack has been presented.

15

Porównanie sił aerodynamicznych działających na połowę torusa i dwa walce o tej samej długości

Padewska A., Szczepaniak P., Wawrzynek A.

Modelowanie Inżynierskie

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2016

|

T. 29, nr 60

52--57

PL

W Eurokodzie PN-EN 1991-1-4 [11] brakuje wytycznych projektowych umożliwiających oszacowanie sił aerodynamicznych działających na obiekty o nietypowym kształcie. W referacie porównano zatem charakter przepływu powietrza o dużych, coraz częściej występujących na świecie prędkościach w pobliżu obiektów w kształcie połowy torusa (np. fragmentu zjeżdżalni wodnej) i dwóch walców o sumarycznej długości równej długości osi połowy torusa, ustawionych poziomo oraz odchylonych od poziomej płaszczyzny pod kątem ß = 45°. Porównano również siły aerodynamiczne działające na połowę torusa - opór aerodynamiczny i poziomą siłę prostopadłą do niego, z siłami działającymi na walce. Wyniki otrzymano na podstawie analiz numerycznych: MES i MOS, wykorzystując moduły: CFD (Computational Fluid Dynamics) i FSI (Fluid-Structure Interaction).

EN

Eurocode EN 1991-1-4 [11] does not include issues concerning wind loads acting on constructions in a non-typical shape. Therefore, in the paper the character of high-speed air flow, which increasingly occurs in the world around objects in the shape of a half - torus (eg. a fragment of a water slide) and two cylinders positioned horizontally and inclined to the horizontal plane at an angle ß = 45° were compared. Also aerodynamic forces acting on a half of the torus - an aerodynamic resistance and a horizontal force perpendicular to the direction of a wind velocity, were compared with forces acting on cylinders. Results are based on numerical analysis: FEM and FVM using the following modules: CFD (Computational Fluid Dynamics) and FSI (Fluid-Structure Interaction).

16

Reducing aeration and cavitation effect in shock absorbers using uid-structure interaction simulation

Czop P., Gniłka J.

Computer Assisted Methods in Engineering and Science

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2016

|

Vol. 23, no. 4

171--189

EN

This paper presents a fluid-structure interaction simulation applicable for evaluating and optimizing hydraulic valve designs. A special emphasis is placed on shim stack valve commonly used in automotive and railway shock absorbers. For simplicity, the problem was effectively reduced to a two-dimensional (2D) problem. This was accomplished by introducing section-lines along which the pressure profile was computed to find and evaluate the global minimum. The global minimum was then treated as the design ranking measure. This ranking function provided a means to choose an optimal design from a set of available design variants. In the presented results, the ranking is problem-specific as it identifies and localizes low pressure zones that are the root causes of both aeration and cavitation effects. The damping force performance was experimentally evaluated for both the baseline and optimized valve design using a shock absorber level test on a servo-hydraulic test rig.

17

Fluid-Structure Interaction Modeling of Aortic Valve Stenosis at Different Heart Rates

Bahraseman H. G., Languri E. M., Yahyapourjalaly N., Espino D. M.

Acta of Bioengineering and Biomechanics

|

2016

|

Vol. 18, no. 3

11--20

EN

Purpose: This paper proposes a model to measure the cardiac output and stroke volume at different aortic stenosis severities using a fluid–structure interaction (FSI) simulation at rest and during exercise. Methods: The geometry of the aortic valve is generated using echocardiographic imaging. An Arbitrary Lagrangian–Eulerian mesh was generated in order to perform the FSI simulations. Pressure loads on ventricular and aortic sides were applied as boundary conditions. Results: FSI modeling results for the increment rate of cardiac output and stroke volume to heart rate, were about 58.6% and –14%, respectively, at each different stenosis severity. The mean gradient of curves of cardiac output and stroke volume to stenosis severity were reduced by 57% and 48%, respectively, when stenosis severity varied from healthy to critical stenosis. Conclusions: Results of this paper confirm the promising potential of computational modeling capabilities for clinical diagnosis and measurements to predict stenosed aortic valve parameters including cardiac output and stroke volume at different heart rates.

18

A numerical approach to the standard model of water hammer with fluid-structure interaction

Henclik S.

Journal of Theoretical and Applied Mechanics

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2015

|

Vol. 53 nr 3

543--555

EN

In the classic water hammer (WH) theory, 1D liquid flow in a quasi-rigid pipe is assumed. When the pipe is flexible or is fixed to the foundation with elastic supports, the dynamic fluid structure interaction (FSI) should be taken into account for more accurate modelling of the system behaviour. The standard model of WH-FSI for a straight pipe reach is governed by fourteen hyperbolic partial differential equations of the first order, two for 1D liquid flow and twelve for 3D motion of the pipe. This model is presented in the paper and an algorithm for its numerical solution based of the method of characteristics is proposed. Basic boundary conditions (BC) are shortly discussed. The important condition at the junction of two subpipes fixed to the foundation with a viscoelastic support is presented in details and a general method of its solution is proposed.

19

Vibro-acoustic analysis of laminated double glazing using the force identification method

Ben Jdidia M, Akrout A, Tounsi D, Fakhfakh T., Haddar M.

Journal of Theoretical and Applied Mechanics

|

2014

|

Vol. 52 nr 4

895--904

EN

This paper presents a procedure for identifying wave forms and excitation frequencies of some forces applied on a given complex fluid-structure coupled system by using only its vibro-acoustic response. The considered concept is called the Independent Component Analysis (ICA) which is based on the Blind Source Separation (BSS). In this work, the ICA method is exploited in order to determine the excitation force applied to a thin-film laminated double glazing system enclosing a thin fluid cavity and limited by an elastic joint. The dynamic response of the studied fluid-structure coupled system is determined by finite element discretization and minimization of the homogenized energy functional of the coupled problem. This response will serve as the input for the ICA algorithm in order to extract the applied excitation.

20

Analysis of fluid-structure interaction of a torus subjected to wind loads

Padewska A., Szczepaniak P., Wawrzynek A.

Computer Assisted Methods in Engineering and Science

|

2014

|

Vol. 21, no. 2

151--167

EN

In the paper the aerodynamic forces acting on a part of a water slide or other object with curved, tubular shape, depending on the section of a torus and value of the wind velocity, were obtained. This was done by means of finite element method (FEM) and finite volume method (FVM) computer simulations, using modules: computational fluid dynamics (CFD) and fluid-structure interaction (FSI) and taking into account the Eurocode EN 1991-1-4.