Numerical prediction of the modal response of flexible cylinders in cross-flow with a current dependent form of damping

• Published in: Journal of marine science and technology Vol. 18; no. 3; pp. 370 - 380
• Main Authors: HUERA-HUARTE F. J., GONZALEZ L. M.
• Format: Journal Article
• Language: English
• Published: Tokyo Springer Japan 01.09.2013; Springer; Springer Nature B.V
• Subjects: Automotive Engineering; Computer simulation; Cylinders; Damping; Eigenvalues; Engineering; Engineering Design; Engineering Fluid Dynamics; Euler-Bernoulli beam equation; Finite element method (FFM); Fluid flow; Fluid mechanics; Long flexible cylinders; Marine; Mathematical analysis; Mathematical models; Mechanical Engineering; Natural frequencies; Numerical analysis; Offshore; Offshore Engineering; Offshore risers; Offshore structures; Offshore tendons; Original Article; Quadratic eigenvalue problem (QEP); Risers; Vibration; Vortex-induced vibrations (VIV); Wake-induced vibrations (WIV); Natural frequencies; Wake-induced vibrations (WIV); Finite element method (FEM); Offshore risers; Offshore tendons; Euler–Bernoulli beam equation; Quadratic eigenvalue problem (QEP); Vortex-induced vibrations (VIV); Long flexible cylinders
• ISSN: 0948-4280; 1437-8213
• DOI: 10.1007/s00773-013-0214-5

A quadratic eigenvalue problem (QEP) was posed in order to study the dynamics of flexible cylinders in cross-flow, simulating slender offshore structures such as risers, catenaries or tendons. The Euler–Bernoulli equation was used to model the structure assuming a fluid loading model, and yielding a quadratic eigenvalue problem that included a form of damping dependent not only on the structural damping itself, but also on the free stream velocity and the fluid force coefficients. We solved the QEP using the finite element method. We also derived a simplified analytical solution in this work for comparison with the QEP, however this solution does not consider changes in tension along the length of the cylinder as the QEP does. In our study, the QEP solutions were first validated against the simplified analytical solution, and also against a well-known experimental dataset obtained in 2003, in which a flexible circular cylinder model was used to model the dynamics of a riser undergoing multi-mode vortex-induced vibrations.