Response prediction of long flexible risers subject to forced harmonic vibration

Abstract

Several research efforts have been directed toward the development of models for response prediction of flexible risers. The main difficulties arise from the fact that the dynamic response of flexible risers involves a highly nonlinear behavior and a self-regulated process. This paper presents a quasi-steady approach for response prediction of oscillating flexible risers. Amplitude-dependent lift coefficients and an increased mean drag coefficient model during synchronization events are considered. Experimental validation of the proposed model is carried out using a 20-meter riser model excited by forced harmonic vibration at its top end. Large variations in the hydrodynamic force coefficients, a low mass-ratio value and synchronization events are the main features of the model presented in this paper. Experimental validation is provided for the asymmetric, transverse, diagonal and third vortex regimes.

Numerical based approach for predicting the response of flexible risers under oscillatory flows at Low Re and KC numbers

“…Results are in good agreement with those published in the literature (see Table I). Additional support is given by the good agreement of the numerical based approach presented in this paper with experimental validation data provided by Riveros et al [24] and discussed below.…”

“…15. Although good agreement was reported by Riveros et al [24], it is still possible to observe some deviations between the simulation results and experimental data in the main cross-flow frequency. The model presented in this paper, as shown in Fig.…”

“…Riveros et al [24] conducted a series of forced oscillation experiments for flexible risers where a 20-meter riser model was tested for different values of and numbers; their experimental model case 1 has the same diameter as (1000) and (7,9) numbers presented here in Fig. 15.…”

“…Moreover, a bi-dimensional model is established using OpenFOAM simulations and employing a single desktop computer. The results presented here consider an experimental validation by Riveros et al [24] in order to demonstrate the use of numerical based approaches to predict the response of flexible risers.…”

Estudo da estática e dinâmica de linhas, sob configuração de catenária, através da identificação geométrica, processamento e análise de imagens digitais.

“…Pode-se mencionar, no campo da experimentação, Riveros et al (2009), Valdivia et al (2007Simos (2006), Simos;Fujarra (2006), Faltinsen et al (1994).…”