DOI
10.11606/T.3.2013.tde-22092014-110644
Documento
Autor
Nome completo
Flávia Milo dos Santos
E-mail
Área do Conhecimento
Data de Defesa
Imprenta
São Paulo, 2013
Pesce, Celso Pupo (Presidente)
Ragazzo, Clodoaldo Grotta
Simos, Alexandre Nicolaos
Sphaier, Sergio Hamilton
Título em português
Impacto hidrodinâmico vertical de corpos axissimétricos através de uma abordagem variacional.
Palavras-chave em português
Abordagem GvKM
Impacto vertical de corpos axissimétricos
Método numérico variacional
Problema de impacto hidrodinâmico
Resumo em português
Título em inglês
Vertical hydrodynamic impact of axisymmetric bodies through a variational approach.
Palavras-chave em inglês
Desingularized techniques
GvKM approach
Hydrodynamic impact problem
Variational numerical method
Vertical impact of axisymmetric bodies
Resumo em inglês
In terms of classical hydrodynamics, the hydrodynamic impact problem is characterized as a boundary problem with moving boundary which position must be determined simultaneously with the solution of the field equation. This feature brings difficulties to get analytical and numerical solutions. In this sense, the purpose of this work is to present a variational method technique specifically designed for the hydrodynamic impact problem of axisymmetric rigid bodies on the free surface. The solution of the nonlinear dynamic equation of the impacting motion depends on the determination of the added mass tensor and its derivative with respect to time at each integration time step. This is done through a variational method technique that leads to a second-order error approximation for the added mass if a first-order error approximation is sought for the velocity potential. This method is an example of desingularized numerical techniques, through which the velocity potential is approximated in a sub-space of finite dimension, formed by trial functions derived from elementary potential solutions, such as poles, dipoles, and vortex rings, which are placed inside the body. The potential problem of hydrodynamic impact, characterized by the dominance of inertial forces, is here formulated by assuming the liquid surface as equipotential, what allows the analogy with the infinity frequency limit in the usual free surface oscillating floating body problem. The method is applied to the vertical hydrodynamic impact of axisymmetric bodies within the so-called Generalized von Kármán Model (GvKM). In such approach, the exact body boundary condition is full-filled and the wet correction is not taken into account. Numerical results for the added mass coefficient for a family of spheroids are presented. Moreover, considerations are made on the effects of the free surface elevation for the specific case of an impacting sphere, through analytical approaches.

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Data de Publicação
2014-10-09

AVISO: O material descrito abaixo refere-se a trabalhos decorrentes desta tese ou dissertação. O conteúdo desses trabalhos é de inteira responsabilidade do autor da tese ou dissertação.
• CASETTA, Leonardo, Pesce, Celso P., and SANTOS, F. M. On the hydrodynamic vertical impact problem: an analytical mechanics approach. Marine Systems & Ocean Technology, 2011, vol. 6, p. 47-57.
• Pesce, Celso P., SANTOS, FLÁVIA M. DOS, and CASETTA, Leonardo. On the Equation of Motion Governing the Dynamics of Vertically Collapsing Buildings [doi:10.1061/(asce)em.1943-7889.0000453]. Journal of Engineering Mechanics [online], 2012, vol. online, p. 1-23.
• SANTOS, FLÁVIA M., CASETTA, Leonardo, and Pesce, Celso P. Application of a variational method to the vertical hydrodynamic impact of axisymmetric bodies [doi:10.1016/j.apor.2012.10.002]. Applied Ocean Research [online], 2013, vol. 39, p. 75-82.
• SANTOS, F. M., and Pesce, Celso P. Further applications of a variational method to the vertical hydrodynamic impact of axisymmetric bodies. In COBEM2013, R. Preto, 2013. 22nd International Congress of Mechanical Engineering.RJ : ABCM, 2013.
Todos os direitos da tese/dissertação são de seus autores
Centro de Informática de São Carlos