Comparison of Strong and Partioned Fluid Structure Code Coupling Methods

2005 ◽  
Author(s):  
E. Longatte ◽  
V. Verreman ◽  
Z. Bendjeddou ◽  
M. Souli
Keyword(s):  
Energy Conservation ◽  
Coupled System ◽  
Added Mass ◽  
Point Of View ◽  
Numerical Dissipation ◽  
Fluid Structure Interactions ◽  
Fluid Structure ◽  
Coupling Procedure ◽  
Flow Induced Vibrations ◽  
Structure Code

As far as flow-induced vibrations are concerned, fluid structure interactions and fluid elastic effects are involved. They may be characterized by parameters like added mass, added damping and added stiffness describing fluid and flow effects on structure motion. From a numerical point of view, identifying these parameters requires numerical simulation of coupled fluid and structure problems. To perform such a multi-physics computation, several numerical methods can be considered involving either a partitioned or a monolithic fluid structure code coupling procedure. Monolithic process is a fully implicit method ensuring the energy conservation of the coupled system. However its implementation may be difficult when specific methods are required for both fluid and structure solvers. The partitioned procedure does not feature the same disadvantage because fluid and structure computations are staggered in time. However a specific attention must be paid to the energy conservation of the full coupled system and one must choose code coupling schemes in order to avoid or to reduce as much as possible numerical dissipation polluting the results. In the present paper, several techniques for fluid structure code coupling are compared. Several configurations are considered and numerical results are discussed in terms of added mass and damping for structures vibrating in fluid at rest. These results contribute to the validation of a full fluid structure code coupling procedure with many possible applications in the fields of fluid structure interactions and flow-induced vibrations.

Experimental and Numerical Analysis of a Coupled Fluid-Structure Subjected to Dynamic Acceleration

2005 ◽  
Author(s):  
Jean-Franc¸ois Sigrist ◽  
Vincent Conessa
Keyword(s):  
Finite Element ◽  
Free Surface ◽  
Linear Model ◽  
Coupled System ◽  
Point Of View ◽  
Time Duration ◽  
Fluid Structure ◽  
Displacement Sensors ◽  
Non Linear ◽  
Coupling Techniques

The present paper deals with a numerical and experimental study carried out on a coupled fluid/structure system subjected to an imposed dynamic acceleration. The coupled system is an clamped/free elastic cylinder surrounded by a heavy, incompressible fluid, contained in a concentric rigid tank, with a fluid free surface. The whole system is subjected to a transverse imposed motion, characterized by a short time duration (∼ 10 ms) and a large acceleration amplitude (∼ 400 m/s2). The principle of the study lies on both an experimental and numerical approach of the problem. This analysis is carried out in order to better understand the dynamic of the coupled system, with industrial application related to the design of embarked naval propulsion nuclear structure. From the numerical point of view, several approaches of the coupled problem are proposed: linear and non linear model are exposed, and various numerical techniques are developed. Strong coupling techniques based on finite element or boundary element are coupled to solve the linear model. Weak coupling techniques are developed to solve the non linear problem. In such technique, the numerical resolution is based on a finite volume method for the fluid problem and finite element method for the structure problem. The fluid and structure problems can be coupled with a staggered explicit or implicit algorithm. From the experimental point of view, a experimental system is designed on a shock table. Structural data (such as displacement, acceleration) are recorded with accelerometers and displacement sensors, fluid data (such as pressure and free surface motion) are recorded with pressure gauge and high-speed numerical camera.

Comparison of Code Coupling Scheme for Simulation of Fluid Structure Problems

2004 ◽  
Author(s):  
E. Longatte ◽  
Z. Bendjeddou ◽  
M. Souli
Keyword(s):  
Numerical Simulation ◽  
Data Transfer ◽  
Laminar Flows ◽  
Coupling Scheme ◽  
Fluid Structure Interactions ◽  
Fluid Structure ◽  
Coupling Process ◽  
First Results ◽  
Flow Induced Vibrations ◽  
Computational Resources

Numerical simulation of industrial multi-physic problems is still a challenge to overcome as it generally requires large computational resources and may involve code coupling with appropriate numerical methods making data transfer possible, quick and accurate. Numerical simulation of fluid structure interactions and particularly of flow-induced vibrations is one of these issues; it is investigated in the present paper. In the present work one focuses his attention on methods for numerical simulation of flow-induced vibrations of tubes and tube bundles in presence of still water or laminar flows. Fluid structure code coupling process is described and first results of validation are presented. Fluid and structure codes are presented in the first section. Numerical scheme for code coupling process are investigated in the second part. Finally results of test cases are discussed in the last section.

scholarly journals Fluid-structure Interactions and Flow Induced Vibrations: A Review

2016 ◽  
Vol 144 ◽  
pp. 1286-1293 ◽  
Author(s):  
R. Parameshwaran ◽  
Sai Jathin Dhulipalla ◽  
Daseswara Rao Yendluri
Keyword(s):  
Fluid Structure Interactions ◽  
Fluid Structure ◽  
Flow Induced Vibrations

Fluid Structure Interactions at Towed Fishing Gears

2004 ◽  
Author(s):  
Mathias Paschen ◽  
Gerd Niedzwiedz ◽  
Hans-Joachim Winkel
Keyword(s):  
Experimental Methods ◽  
Point Of View ◽  
The Other ◽  
Fishing Gear ◽  
Fluid Structure Interactions ◽  
Fluid Structure ◽  
Other Hand ◽  
Fishing Gears ◽  
The One ◽  
Surrounding Fluid

From the point of view of mechanics, trawls are considered as extremely flexible and partly extensible rope and net structures which are exposed to flow. Form and loads of such gears mainly depend on the corresponding velocity of inflow and also on the so-called rigging elements that are required for the horizontal and vertical spreading of the fishing gear. At the same time the fishing gear is acting on the surrounding fluid. These reactions can on the one hand lead to unsteady states in the fishing gear. On the other hand changes of pressure and velocity can be detected by the fish and can possibly influence the selectivity of the fishing gear. This lecture is focused on the presentation of special numerical and experimental methods both for calculating large net systems and for analysing the reactions of the structure to the fluid.

Simulation of Fluid-Structure Interaction of Crossflow Through a Tube Bundle and Experimental Validation

2017 ◽  
Author(s):  
Landon Brockmeyer ◽  
Jerome Solberg ◽  
Elia Merzari ◽  
Yassin Hassan
Keyword(s):  
Solid Mechanics ◽  
Tube Bundle ◽  
Fluid Structure Interaction ◽  
Spectral Element ◽  
Fluid Structure Interactions ◽  
Low Velocity ◽  
Simulation Code ◽  
Fluid Structure ◽  
Structure Interaction ◽  
Flow Induced Vibrations

Fluid-structure interactions are complex, multi-physics phenomena of consequence for many fluid-flow domains. Modern multi-physics codes are becoming capable of simulating with great accuracy the interaction between fluid and structure dynamics. While fluid-structure interactions can occur in many forms, flow-induced vibrations are of particular interest. Such vibrations can result in the fatigue and even failure of a vibrating geometry. The prediction and minimization of flow induced vibrations are of particular importance for heat exchangers, which commonly contain bundles of tubes experiencing high-velocity crossflow. The present study simulates the fluid-structure interaction for flexibly mounted tube bundles undergoing crossflow and compares the results with experiment. The simulation code consists of a spectral-element fluid solver directly coupled with a finite-element solid mechanics solver. The fluid solver locally adapts the fluid mesh to accommodate the moving solids. In order to minimize computational expense, low Reynolds number flows are considered, allowing for a thin, pseudo 2-D domain. The flow remains laminar for the majority of the domain, with local areas of turbulence. The pins are connected to springs that supply a restorative force equivalent to the flexible mounts of the corresponding experiment. Fluid-only simulations are performed for flow spanning low to moderate velocities and compared visually with experimental flow visualizations. Coupled fluid-structure interactions are simulated with low velocity and vibration amplitudes. The measured vibration amplitudes of the simulation agree well with those of the experiment.

A Numerical Investigation Into the Value of Added Mass Coefficient for Circular Cylinders

2005 ◽  
Author(s):  
H. Karadeniz
Keyword(s):  
Hydrodynamic Pressure ◽  
Added Mass ◽  
Offshore Structures ◽  
Circular Cylinders ◽  
Element Formulation ◽  
Fluid Structure Interactions ◽  
Shells Of Revolution ◽  
Fluid Structure ◽  
Mass Coefficient ◽  
Added Masses

This paper presents a general axi-symmetrical solid element to be used mainly for the calculation of added masses of water surrounding members of offshore structures, and in general, for multi-purposes such as analyses of shells of revolution, circular beams and plates, axi-symmetrical structures and soils, plane stress/strain problems. Since one element type is used for modeling of different media such as structures, soil and water, the element is very suitable to solve interaction problems. The element is derived parametrically so that changing values of parameters can generate flexible geometrical shapes in exact forms. In the element formulation, a constant shear locking is used to solve bending problems of beam like structures. A similar fluid element is also formulated to analyze fluid-structure interactions and to determine added masses of co-vibrating water. The added mass is calculated from hydrodynamic pressures, which are produced by fluid-structure interactions. In the paper, a special solution algorithm is presented for the coupled eigenvalue problem of the interaction. An analytic calculation of the added mass is also presented for members along which a constant variation of hydrodynamic pressure occurs. A couple of examples are provided to demonstrate applications of the elements explained. Added mass coefficients of offshore structural members (tubular members) are investigated for practical uses.

Coupling Analysis of Liquid Sloshing and Structural Vibration Using General Software

2014 ◽  
Vol 137 (1) ◽  
Author(s):  
C. F. Zhu ◽  
G. A. Tang ◽  
M. Y. Zhang
Keyword(s):  
Modal Analysis ◽  
Mass Matrix ◽  
Synthesis Method ◽  
Coupled System ◽  
Structural Vibration ◽  
Fluid Structure Interactions ◽  
Fluid Structure ◽  
Elastic Tank ◽  
Steady Heat Conduction ◽  
Steady Heat

In this paper, a convenient modal analysis method for the linear coupled vibration of a container that is partially filled with a fluid is introduced. This problem is important for various reasons, such as stability analysis. The fluid-structure interactions in an elastic tank with an incompressible liquid are assumed to produce small vibrations. Reduced symmetric finite element equations of the system are acquired according to the component mode synthesis method. Considering that the liquid satisfies the same governing equation as steady heat conduction, general programs can be used to calculate the mass matrix and stiffness matrix of the coupled system. Then, modal analysis of the liquid container using general software, e.g., MSC Nastran, that ensures accuracy and stableness in the process, is applied to demonstrate that this method can determine the modal frequency in a fluid-structure coupled system.

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