Tesis Doctoral
DOI
10.11606/T.3.2013.tde-22092014-110644
Documento
Autor
Nombre completo
Flávia Milo dos Santos
Dirección Electrónica
Área de Conocimiento
Fecha de Defensa
Publicación
São Paulo, 2013
Director
Tribunal
Pesce, Celso Pupo (Presidente)
Ragazzo, Clodoaldo Grotta
Simos, Alexandre Nicolaos
Sphaier, Sergio Hamilton
Título en portugués
Impacto hidrodinâmico vertical de corpos axissimétricos através de uma abordagem variacional.
Palabras clave en portugués
Abordagem GvKM
Impacto vertical de corpos axissimétricos
Método numérico variacional
Problema de impacto hidrodinâmico
Resumen en portugués
Título en inglés
Vertical hydrodynamic impact of axisymmetric bodies through a variational approach.
Palabras clave en inglés
Desingularized techniques
GvKM approach
Hydrodynamic impact problem
Variational numerical method
Vertical impact of axisymmetric bodies
Resumen en inglés
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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Fecha de Publicación
2014-10-09

ADVERTENCIA: El material descrito abajo se refiere a los trabajos derivados de esta tesis o disertación. El contenido de estos documentos es responsabilidad del autor de la tesis o disertación.
• 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 los derechos de la tesis/disertación pertenecen a los autores
Centro de Informática de São Carlos