Integral transform solution for fluid force investigation of a flexible circular cylinder subject to vortex-induced vibrations

• Published in: Journal of marine science and technology Vol. 21; no. 4; pp. 663 - 678
• Main Authors: Gu, Jijun, Duan, Menglan
• Format: Journal Article
• Language: English
• Published: Tokyo Springer Japan 01.12.2016; Springer; Springer Nature B.V
• Subjects: Automotive Engineering; Computational fluid dynamics; Cylinders; Differential equations; Engineering; Engineering Design; Engineering Fluid Dynamics; Fluid mechanics; Fluids; Integral transforms; Investigations; Marine; Mathematical analysis; Mathematical models; Mechanical Engineering; Offshore Engineering; Original Article; Transforms; Vibration; Vortex-induced vibrations; Vortex-induced vibrations; Flexible cylinder; Towing tank; Model test; Integral transform; Fluid force
• ISSN: 0948-4280; 1437-8213
• DOI: 10.1007/s00773-016-0381-2

In the present paper, fluid force distribution of a long flexible cylinder subject to vortex-induced vibrations is investigated by Generalized Integral Transform Technique (GITT). This method is using experimental response data as input, and then implementing GITT to transfer the governing differential equations to ordinary differential equations. Therefore, the selection of truncation order could be analyzed to avoid the error induced by the high-mode response. Once each mode contribution of fluid force is obtained, the analytical inversion transfer recovers the fluid force. An experiment was carried out in a towing tank and the experimental response was accurately measured and used as input, then GITT was performed to calculate the fluid force distribution of the long flexible cylinder. The comparison between the numerical results from GITT and the experimental results from load cell verified the capability and availability of the proposed method. If one can use this method for lower modes, then one certainly can extend the method for higher modes. Two experimental cases from the literature were evaluated and good agreement was obtained based on the spatio-temporal evolutions of the lift coefficient and the mode numbers. Since this method is easy to implement, it could be an alternative method to investigate fluid force of such slender structures.