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.

Transient Dynamic Responses of an Integrated Air-Liquid-Elastic Tank Interaction System Subject to Earthquake Excitations

2008 ◽  
Author(s):  
Ye Ping Xiong ◽  
Jing Tang Xing
Keyword(s):  
Dynamic Behaviour ◽  
Liquid Sloshing ◽  
Dynamic Responses ◽  
Design Stage ◽  
Fluid Structure Interactions ◽  
Fluid Structure ◽  
Transient Dynamic ◽  
Interaction System ◽  
Three Phase ◽  
Elastic Tank

Sloshing problems in partially filled tanks are of increasing concerns in many engineering fields such as marine, chemical, aerospace engineering and automobile industry. The interactive dynamic behaviour of liquid and tank due to their interaction under various loading conditions can have vital impact on the integrity and safe operation of the system. Studies of liquid sloshing and its dynamic effect on the containers are necessary in the early design stage. Currently, most investigations on sloshing problems mainly focus on the analysis of liquids in rigid tanks where the fluid-structure interactions were neglected. Studies on fluid-structure interactions are limited to two phases of liquid-tank interactions. Three phase interactions involving air, liquid and elastic tank are rarely considered. In this paper, the dynamic behaviour of an air-liquid-elastic tank interaction system is investigated. The tank filled with air and liquid is supported at four equally spaced positions around the outer shell. The dynamic pressure in the liquid / air and the displacement in the elastic solid are used as variables to formulate the numerical model incorporating a substructure-subdomain approach and numerical simulations are presented based on a developed computer program. The natural frequencies in association with the corresponding vibration modes and the transient dynamic responses of the complex coupled system subject to earthquake excitations are presented. The ground motion data recorded from El-Centro earthquake is used as an earthquake load to the system. Different interactive cases are examined. These include liquid sloshing in a rigid tank, air-liquid interactions in a rigid tank, liquid-elastic tank interactions and three phase air-liquid-tank interactions. The numerical results obtained reveal the complex coupled behaviour of the system as well as the air effect on dynamic displacement and sloshing pressure. This study provides information for the design of liquid / gas filled tanks in which sloshing behaviour is of interest.

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.

Dynamic Analysis and Design of LNG Tanks Considering Fluid Structure Interactions

2008 ◽  
Author(s):  
Y. P. Xiong ◽  
J. T. Xing
Keyword(s):  
Numerical Simulations ◽  
Sea Water ◽  
Dynamic Responses ◽  
Fluid Structure Interactions ◽  
Dynamic Design ◽  
Fluid Structure ◽  
Water Interaction ◽  
Lng Tank ◽  
Elastic Tank ◽  
Natural Characteristics

Following a general description and analysis of the fundamental criteria for the dynamic design concerning dynamic stiffness, strength and environment issues, it is considered that the natural characteristics of the dynamic system and the dynamic responses of the system subject to various dynamic loads are two key critical issues in the dynamic design. Therefore, for the dynamic design of a LNG tank filled with liquid and operated on seaway, it is necessary to accurately predict its natural characteristics and dynamic response considering fluid structure interactions. To address these two key issues in the dynamic design stage, the developed computer software based on a mixed displacement–pressure finite element model to complete fluid-structure interaction analysis is introduced. An integrated internal liquid-tank-external water interaction system investigated by numerical simulations is summarised to consider the two issues involving the dynamic design of LNG tanks. The five studied cases include: i) 50% filled LNG liquid in a fixed rigid tank, ii) elastic tank only, iii) 50% filled LNG liquid-elastic tank interaction, iv) empty elastic tank-external sea water interaction and v) internally 50% filled LNG liquid-elastic tank-external sea water interaction. The calculated results are compared to reveal the coupling effects on the dynamic design of LNG tanks. To further demonstrate the effects of the natural characteristics affected by different interactions on the dynamic responses involving the dynamic strength, stiffness and vibration environment problems considered in dynamic design, the numerical simulations of the studied systems subject to regular sea wave excitations and earthquake excitations are carried out. The dynamic displacements for stiffness analysis, the dynamic stress for strength analysis and vibration level for dynamic environment analysis are presented and discussed. Guidelines provided in this paper maybe useful for dynamic designs of LNG tank operating in complex marine environments.

Fluid-Structure Interactions

2009 ◽  
Author(s):  
Michael Paidoussis ◽  
Stuart Price ◽  
Emmanuel de Langre
Keyword(s):  
Fluid Structure Interactions ◽  
Fluid Structure

Experimental Mixing Parameterization Due to Multiphase Fluid � Structure Interactions

2010 ◽  
Vol 5 (2) ◽  
pp. 1-8
Author(s):  
Ranis N. Ibragimov ◽  
◽  
Akshin S. Bakhtiyarov ◽  
Margaret Snell ◽  
◽  
...  
Keyword(s):  
Fluid Structure Interactions ◽  
Fluid Structure ◽  
Multiphase Fluid

scholarly journals Cross-Flow Tidal Turbines with Highly Flexible Blades—Experimental Flow Field Investigations at Strong Fluid–Structure Interactions

Energies ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 797
Author(s):  
Stefan Hoerner ◽  
Iring Kösters ◽  
Laure Vignal ◽  
Olivier Cleynen ◽  
Shokoofeh Abbaszadeh ◽  
...  
Keyword(s):  
Flow Field ◽  
High Speed ◽  
Cross Flow ◽  
Speed Ratio ◽  
Fluid Structure Interactions ◽  
Dimensional Parameter ◽  
Fluid Structure ◽  
Passive Flow Control ◽  
Tidal Turbines ◽  
Tidal Turbine

Oscillating hydrofoils were installed in a water tunnel as a surrogate model for a hydrokinetic cross-flow tidal turbine, enabling the study of the effect of flexible blades on the performance of those devices with high ecological potential. The study focuses on a single tip-speed ratio (equal to 2), the key non-dimensional parameter describing the operating point, and solidity (equal to 1.5), quantifying the robustness of the turbine shape. Both parameters are standard values for cross-flow tidal turbines. Those lead to highly dynamic characteristics in the flow field dominated by dynamic stall. The flow field is investigated at the blade level using high-speed particle image velocimetry measurements. Strong fluid–structure interactions lead to significant structural deformations and highly modified flow fields. The flexibility of the blades is shown to significantly reduce the duration of the periodic stall regime; this observation is achieved through systematic comparison of the flow field, with a quantitative evaluation of the degree of chaotic changes in the wake. In this manner, the study provides insights into the mechanisms of the passive flow control achieved through blade flexibility in cross-flow turbines.

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