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COBEM 2017
24th ABCM International Congress of Mechanical Engineering
Statistical calibration of 2DOF vortex-induced vibration phenomenological model.
Submission Author:
Gabriel Mario Guerra Bernadá , RJ , Brazil
Co-Authors:
Gabriel Mario Guerra Bernadá, Rodolfo S. M. Freitas, Bruno Soares, Fernando Rochinha
Presenter: Gabriel Mario Guerra Bernadá
doi://10.26678/ABCM.COBEM2017.COB17-2478
Abstract
The vortex-induced vibrations of floating structures play an important role in the design of offshore engineering. The accurate prediction of structural instability is extremely important due that the vortex shedding behind bluff bodies may lead to degradation of structural performance or even structural failure. Analytical VIV models can be represented by numerous approaches to modeling both the structure and fluid. The CFD (Computational Fluid Dynamics) approaches consists of solving the Navier-Stokes equations directly, mostly limited by heavily computational costs that many times very difficult to satisfy in the practical engineering. In this sense, semi-empirical models are an alternative approach, where the fluid dynamic forces acting on the structure are emulated by phenomenological equations and can be a very useful tool in wide industrial applications. The purpose this work is to present a phenomenological model of vortex-induced vibrations for spring-mounted rigid cylinder structures putting the parameter variability in the general context of Uncertainty Analysis doing first a sensitivity analysis for input empirical parameters of the model using the Adaptive Sparse Grid Stochastic Collocation method (ASGSC). After this, a backward parameter estimation analysis is done using a Bayesian technique to calibrate these empirical parameters, by means of exploring posterior density functions. Synthetic data were generated as reference simulating experimental data to show the calibration technique used. This kind of analysis can help to understand the behavior of the structure to critical situations as well the effects of varying empirical parameters in the response variables. The influence of these parameters and other coefficients that affect the dynamical response is analyzed and also discussed.
Keywords
calibration, vortex induced vibrations, reduced order model
