Modelo hidro-elástico para simular as vibrações induzidas por vórtices em cabos submersos. / Hidro-elastic model to stimulate vortex-induced vibrations in submerged cables.

AUTOR(ES)

Lauro Massao Yamada da Silveira

DATA DE PUBLICAÇÃO

2009

RESUMO

The present work proposes a qualitative numerical study of a hydro-elastic model in order to simulate vortex-induced vibrations in submerged cables. The model is composed of a coupled system of equations describing the structure and the fluid. The structure is modeled through a classical elastic oscillator and discretized using a lumped mass approach. The fluid is modeled through discrete oscillators based on phenomenological models using Van der Pol or Ginzburg- Landau type equations. The coupling between these two oscillators is carried by the lift force. The study was carried in order to verify which response behavior can be obtained by using such phenomenological models and also, to evaluate their potential to be used in the offshore industry. In order to accomplish that, the model must provide reliable answers and must allow fast responses when it comes to simulation time. In this sense, a numerical model was developed to allow the time domain integration of this hydro-elastic model. The numerical integration is performed by a simple explicit Euler algorithm and allows dealing with non-linearities of both oscillators, elastic and fluid. A set of conditions was numerically simulated, including top tensioned risers and catenary. Simulations indicate a high level of coupling between the two oscillators and thus resonance is achieved in most part of the cases. With respect to the structural oscillator analysis, it was possible to observe interesting phenomena such as lock-in, travelling waves and also the third harmonic observed in some experiments and reported in the literature. Regarding the feasibility of the model usage in the daily offshore industry life, it seems possible once the model generally runs fast and some promising results were achieved.

ASSUNTO(S)

vórtices dos fluídos (simulação numérica) mooring lines semi-submersibles offshore structures fluid vortices (numerical simulation) cabos de amarração estruturas offshore semi-submersíveis

Documentos Relacionados

• Vortex-Induced Injectable Silk Fibroin Hydrogels
• Parametric analysis of a phenomenological model for vortex-induced motions of monocolumn platforms
• Wind tunnel test for vortex-induced vibration of vehicle-bridge system section model
• Analytic-Numerical study of Vortex-Induced Vibrations in a vertical rigid riser, subjected to tension fluctuation and its influence in fatigue.
• Reciclagem de fios e cabos elétricos.