Estudo numérico do sloshing utilizando o método smoothed particle hydrodynamics
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Data
2018-03-12
Autores
Barbosa, Danilo de Almeida
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Universidade Federal do Espírito Santo
Resumo
The increasing exploitation of offshore oil and consequent increase in the number of FPSO platforms and vessels to transport this fluid requires increasing attention to the effects produced by the free surface oscillation in transport tanks and storage of liquid petroleum and liquefied gas. In this thesis, a study on the impacts on the sidewalls of rectangular containers provoked by sloshing is proposed. The lagrangian free-particle method known as SMOOTHED PARTICLE HYDRODYNAMICS-SPH, which in its genuine form makes use of the force from the Lennard-Jones potential to keep the particles inside the domain was applied. Contributions to the method were also performed, such as the alteration in the search system of neighboring particles; proposal of a relation between the number of virtual particles and smoothing length; and pointing to an "optimal number" of contour particles. Besides the control of the correction parameters that allowed to reduce the processing time. However, the most relevant contribution was the creation of a new contour treatment technique using the COULOMB FORCE, which proved to be more robust than the classical technique (Lennard-Jones). The mathematical modeling passed through the equations of mass conservation and conservation of linear momentum. With this, two-dimensional simulations with different geometries were made and after identification of the causes and effects produced by sloshing, suppression mechanisms were installed inside the tanks. For validation of the models, three experimental tests were carried out by different authors, two of whom simulated the behavior of tanks under the action of horizontal forces on a reduced scale, and a third the movement of pitch with the tank on an inverted pendulum platform. The quantitative data of the hydrodynamic pressure were collected by transducers installed on the walls of the containers. The tests followed with baffles of two different heights and with arrow-shaped deflectors acting as fins. All baffles were effective in reducing normal stresses, however, those in the arrow shape presented higher than standard vertical baffles, indicating that adequate morphology may reduce sloshing damage.
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Coulomb, Força de , Método smoothed particle hydrodynamics (SPH) , Tratamento de contornos