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Odd M Faltinsen - One of the best experts on this subject based on the ideXlab platform.
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linear sloshing in a 2d rectangular Tank with a flexible sidewall
Journal of Fluids and Structures, 2017Co-Authors: Ida Marlen Strand, Odd M FaltinsenAbstract:Abstract A 2D rectangular sloshing Tank with a flexible sidewall have been studied analytically and numerically, with a focus on the coupling between sloshing and the flexible wall. This analysis introduces new knowledge of the effect of internal motions and flow in a membrane structure with a free surface, such as closed flexible fish cages. A framework for analyzing coupled fluid–membrane interaction in the time, and frequency domain in 2D have been developed. The analytical solution gives new knowledge about the effect of the deformations on the linear pressure inside the Tank. Coupled eigenfrequencies and the transfer functions for two different membrane lengths due to sway excitation have been found both analytically and numerically. The analytical and numerical results agree. The eigenfrequencies of the system are highly dependent on both the tension and the 2D membrane length. If we consider a given value of tension, then the eigenfrequency of the coupled system is smaller than the sloshing frequency of the Rigid Tank for any given n . If the tension is small, and we consider a given sloshing frequency of the Rigid Tank, then there can be more than n eigenfrequencies of the coupled system that is lower than the sloshing frequency of the Rigid Tank. For large tensions, the eigenfrequencies of the system become the sloshing frequency of a Rigid Tank. For low tensions, numerical challenges for the direct numerical solution for frequencies close to the natural sloshing frequencies were pointed out.
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asymptotic modal approximation of nonlinear resonant sloshing in a rectangular Tank with small fluid depth
Journal of Fluid Mechanics, 2002Co-Authors: Odd M Faltinsen, A N TimokhaAbstract:The modal system describing nonlinear sloshing with inviscid flows in a rectangular Rigid Tank is revised to match both shallow fluid and secondary (internal) resonance asymptotics. The main goal is to examine nonlinear resonant waves for intermediate depth/breadth ratio 0.1 [lsim ] h / l [lsim ] 0.24 forced by surge/pitch excitation with frequency in the vicinity of the lowest natural frequency. The revised modal equations take full account of nonlinearities up to fourth-order polynomial terms in generalized coordinates and h / l and may be treated as a modal Boussinesq-type theory. The system is truncated with a high number of modes and shows good agreement with experimental data by Rognebakke (1998) for transient motions, where previous finite depth modal theories failed. However, difficulties may occur when experiments show significant energy dissipation associated with run-up at the walls and wave breaking. After reviewing published results on damping rates for lower and higher modes, the linear damping terms due to the linear laminar boundary layer near the Tank's surface and viscosity in the fluid bulk are incorporated. This improves the simulation of transient motions. The steady-state response agrees well with experiments by Chester & Bones (1968) for shallow water, and Abramson et al. (1974), Olsen & Johnsen (1975) for intermediate fluid depths. When h / l [lsim ] 0.05, convergence problems associated with increasing the dimension of the modal system are reported.
P. K. Sinha - One of the best experts on this subject based on the ideXlab platform.
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dynamic response analysis of a liquid filled cylindrical Tank with annular baffle
Journal of Sound and Vibration, 2004Co-Authors: K. C. Biswal, S. K. Bhattacharyya, P. K. SinhaAbstract:Abstract Baffles are generally used as damping devices in liquid storage Tanks. The focus of the present paper is to study the influence of a baffle on the dynamic response of a partially liquid-filled cylindrical Tank. A baffle is assumed here to have the shape of a thin annular circular plate. The natural frequencies of an inviscid and incompressible liquid are determined for varying positions and dimensions of a baffle attached normal to the Tank wall. The flexibility of both the baffle and the Tank are considered in studying the effects of liquid–baffle and liquid–Tank interactions on the sloshing mode frequencies. Finite element codes are developed and are then used to analyze both the liquid domain and the structural domain (i.e., the Tank and the baffle). The coupled vibration frequencies of the Tank–baffle system are computed considering the effect of sloshing of liquid. The results obtained for a liquid-filled elastic Tank without a baffle and a Rigid Tank with a Rigid baffle are in good agreement with the available results. The slosh amplitude of liquid in a Rigid Tank with and without a Rigid baffle is studied under translational base excitation. The effects of the Tank wall and baffle flexibility on the slosh response are also investigated.
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free vibration analysis of liquid filled Tank with baffles
Journal of Sound and Vibration, 2003Co-Authors: K. C. Biswal, S. K. Bhattacharyya, P. K. SinhaAbstract:The natural frequencies of liquid in a liquid-filled cylindrical Rigid Tank without and with baffles are evaluated. An annular plate is used as a baffle, which is fitted to the inner periphery of a cylindrical Tank. Both Rigid and flexible baffles are considered. Finite elements are used to discretize both the liquid and the structural domain. The slosh frequencies of liquid are computed for different dimensions, thicknesses and positions of baffles, both Rigid and flexible considering the circumferential wave number as one. The axisymmetric and other asymmetric modes are not studied. The results obtained for Rigid baffle case are comparable with the existing results. The coupled vibration frequencies of the Tank-flexible-baffle system are computed considering the effect of sloshing of liquid.
Dongpyo Hong - One of the best experts on this subject based on the ideXlab platform.
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the vibration performance experiment of tuned liquid damper and tuned liquid column damper
Journal of Mechanical Science and Technology, 2006Co-Authors: Youngmoon Kim, Kipyo You, Jieun Cho, Dongpyo HongAbstract:Tuned Liquid damper and Tuned Liquid Column are kind of passive mechanical damper which relies on the sloshing of liquid in a Rigid Tank for suppressing structural vibrations. TLD and TLCD are attributable to several potential advantages - low costs ; easy to install in existing structures ; effective even for small-amplitude vibrations. In this paper, the shaking table experiments were conducted to investigate the characteristics of water sloshing motion in TLD (rectangular, circular) and TLCD. The parameter obtained from the experiments were wave height, base shear force and energy dissipation. The shaking table experiments show that the liquid sloshing relies on amplitude of shaking table and frequency of Tank. The TLCD was more effective control vibration than TLD.
Miriam Patricia Choquehuanca Condori - One of the best experts on this subject based on the ideXlab platform.
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Seismic actions on reinfoced concrete cylindrical Tanks
2017Co-Authors: Miriam Patricia Choquehuanca CondoriAbstract:Resumo: O objetivo deste trabalho é apresentar a teoria atual e estudar o comportamento dinâmico de reservatórios cilíndricos de concreto armado, apoiados no solo, para armazenagem de líquidos e submetido a ações sísmicas, baseado nas normas vigentes nos EUA (ACI 350), Europa (EUROCODE 8), Peru (NTE 030) e Brasil (NBR 15421). São utilizados diferentes tipos de análises a fim de verificar, através da comparação de resultados, se as normas e recomendações disponíveis hoje em dia são equivalentes e adequadas para a realidade brasileira. Entre os modelos para a análise hidrodinâmica temos os modelos de Malhortra, Haroun, Newmark & Rosemblueth e o modelo mecânico de G. W. Housner, sendo este último o procedimento para projetos sísmicos mais comuns para reservatórios rígidos onde a pressão hidrodinâmica do líquido é considerada dividida em duas partes: uma pressão impulsiva (impacto do líquido) e outra parte convectiva (oscilação do líquido). No Brasil não existe uma norma especifica para o projeto de reservatórios de concreto armado. A utilização da NBR 15421 "Estruturas Resistentes a Sismo-Procedimento," poderia ser insuficiente para o projeto, e possivelmente ao complementá-la com as normas sugeridas neste trabalho (ACI 350 e EUROCODE 08) há a possibilidade de encontrar contradições, ou, bem, diferenças significativas nos resultados. É apresentado o procedimento de projeto sísmico por meio de um caso pratico, além dos modelos numéricos tridimensionais com a ajuda do programa SAP2000. Considerando as propriedades elásticas e geométricas do material, a geometria do reservatório de armazenagem e o espectro de resposta da análise modal, são avaliados a força cortante e o momento na base e altura máxima de onda, através da ACI 350.3-06, EUROCODE 08, NTE 030 e NBR 15421. É ainda apresentada a comparação dos procedimentos propostos pelas quatro normas, e a influencia que cada uma delas representa neste tipo de análise. As normas americanas e européias são consideradas por serem duas referências importantes na análise dinâmica de reservatórios de concreto.ABSTRACT: The purpose of this work will be to present the current theory and study the dynamic behavior of a reinforced concrete Tank, with cylindrical form, supported in the floor, for the storage of liquid, based on the current codes in the USA (ACI 350), EUROPA (EUROCODE 8), Peru (NTE 030) and Brazil (NBR 15421), using different analysis types in order to verify by comparing results, if the codes and recommendations today are equivalent and appropriate for the Brazil reality. For the hydrodynamic analysis may mention the Malhortra, Haroun, Newmark & Rosemblueth models and the mechanic model proposed by G. W. Housner, the latter being the most common procedure for Rigid Tank where the hydrodynamic pressure of the liquid is considered into two parts: a impulse pressure (impulse of the liquid) and a convective pressure (oscillation of the liquid). In Brazil there is no specific code for the design of reinforced concrete Tanks. The use the code of Brazil: NBR 15421 Estruturas Resistentes a Sismo - Procedimento" could be insufficient for the project, and possibly complementing with the suggested codes in this work (ACI 350 and EUROCODE 08 codes), there are some possibilities to find contradictions, or, significant differences in the results. It presents the seismic design procedure through a practical case, besides presenting three-dimensional numerical models with the help of the SAP2000 program, considering the geometric and elastic properties of the material, the geometry of the storage Tank and the spectral modal dynamic analysis. Are evaluated the sheer force, moment at the base and maximum wave height, by ACI 350.3-06, EUROCODE 08, NTE 030 and NBR 15421. It will be presented the comparison of the procedures proposed by codes and the influence of each one of them presents in this analysis type. The American and European code are considered because they are an important reference in the dynamic analysis of concrete Tanks
Miriam Patricia - One of the best experts on this subject based on the ideXlab platform.
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Seismic actions on reinfoced concrete cylindrical Tanks
[s.n.], 2018Co-Authors: Choquehuanca Condori, Miriam PatriciaAbstract:Orientador: Isaias VizottoDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Civil, Arquitetura e UrbanismoResumo: O objetivo deste trabalho é apresentar a teoria atual e estudar o comportamento dinâmico de reservatórios cilíndricos de concreto armado, apoiados no solo, para armazenagem de líquidos e submetido a ações sísmicas, baseado nas normas vigentes nos EUA (ACI 350), Europa (EUROCODE 8), Peru (NTE 030) e Brasil (NBR 15421). São utilizados diferentes tipos de análises a fim de verificar, através da comparação de resultados, se as normas e recomendações disponíveis hoje em dia são equivalentes e adequadas para a realidade brasileira. Entre os modelos para a análise hidrodinâmica temos os modelos de Malhortra, Haroun, Newmark & Rosemblueth e o modelo mecânico de G. W. Housner, sendo este último o procedimento para projetos sísmicos mais comuns para reservatórios rígidos onde a pressão hidrodinâmica do líquido é considerada dividida em duas partes: uma pressão impulsiva (impacto do líquido) e outra parte convectiva (oscilação do líquido). No Brasil não existe uma norma especifica para o projeto de reservatórios de concreto armado. A utilização da NBR 15421 "Estruturas Resistentes a Sismo-Procedimento," poderia ser insuficiente para o projeto, e possivelmente ao complementá-la com as normas sugeridas neste trabalho (ACI 350 e EUROCODE 08) há a possibilidade de encontrar contradições, ou, bem, diferenças significativas nos resultados. É apresentado o procedimento de projeto sísmico por meio de um caso pratico, além dos modelos numéricos tridimensionais com a ajuda do programa SAP2000. Considerando as propriedades elásticas e geométricas do material, a geometria do reservatório de armazenagem e o espectro de resposta da análise modal, são avaliados a força cortante e o momento na base e altura máxima de onda, através da ACI 350.3-06, EUROCODE 08, NTE 030 e NBR 15421. É ainda apresentada a comparação dos procedimentos propostos pelas quatro normas, e a influencia que cada uma delas representa neste tipo de análise. As normas americanas e européias são consideradas por serem duas referências importantes na análise dinâmica de reservatórios de concretoAbstract: The purpose of this work will be to present the current theory and study the dynamic behavior of a reinforced concrete Tank, with cylindrical form, supported in the floor, for the storage of liquid, based on the current codes in the USA (ACI 350), EUROPA (EUROCODE 8), Peru (NTE 030) and Brazil (NBR 15421), using different analysis types in order to verify by comparing results, if the codes and recommendations today are equivalent and appropriate for the Brazil reality. For the hydrodynamic analysis may mention the Malhortra, Haroun, Newmark & Rosemblueth models and the mechanic model proposed by G. W. Housner, the latter being the most common procedure for Rigid Tank where the hydrodynamic pressure of the liquid is considered into two parts: a impulse pressure (impulse of the liquid) and a convective pressure (oscillation of the liquid). In Brazil there is no specific code for the design of reinforced concrete Tanks. The use the code of Brazil: NBR 15421 Estruturas Resistentes a Sismo - Procedimento" could be insufficient for the project, and possibly complementing with the suggested codes in this work (ACI 350 and EUROCODE 08 codes), there are some possibilities to find contradictions, or, significant differences in the results. It presents the seismic design procedure through a practical case, besides presenting three-dimensional numerical models with the help of the SAP2000 program, considering the geometric and elastic properties of the material, the geometry of the storage Tank and the spectral modal dynamic analysis. Are evaluated the sheer force, moment at the base and maximum wave height, by ACI 350.3-06, EUROCODE 08, NTE 030 and NBR 15421. It will be presented the comparison of the procedures proposed by codes and the influence of each one of them presents in this analysis type. The American and European code are considered because they are an important reference in the dynamic analysis of concrete TanksMestradoEstruturasMestra em Engenharia Civi
