Investigating cross-flow vortex-induced vibration of top tension risers with different aspect ratios

Liu, Guijie; Li, Haiyang; Xie, Yingchun; Incecik, Atilla; Li, Zhixiong

doi:10.1016/j.oceaneng.2020.108497

Cited by 8 publications

(3 citation statements)

References 29 publications

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“…In addition, according to DNV-RP-F105 Sect. 6.8 [45], the effective length of a free span can be determined using Equation (23). However, in the case of fixed-fixed support, the effective length is equivalent to the length of the pipe (i.e., L e f f = L).…”

Section: Determination Of Natural Frequency Of a Long Free-spanning P...mentioning

confidence: 99%

“…For instance, free-spanning pipelines, due to the roughness of the seafloor, can be distinguished as single free-span and multiple free-span pipelines [1][2][3][4][5][6][7][8]. From an engineering point of view, one of the more widely recognized root causes of structural pipeline collapse is a free span in which the unsupported pipeline becomes very vulnerable, due to (1) being over-stressed by the pipe's self-weight and its contents [15,18,19] and (2) vortex-induced vibration-based fatigue from the current varying with time [20][21][22][23]. In this sense, if the free span cannot be avoided, it is important to determine the maximum allowable length and justify the actual free span accordingly.…”

Section: Introductionmentioning

confidence: 99%

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An Analytical Expression for the Fundamental Frequency of a Long Free-Spanning Submarine Pipeline

Phuor,

Trapper,

Ganz

2023

Mathematics

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The DNVGL-RP-F105 guidelines provide essential techniques for the preliminary design of undersea pipelines. However, its approximations for static displacement and the natural frequency of the pipe are restricted to cases where the ratio of the pipe’s diameter to its length (L/D) is less than 140. This limitation poses challenges for longer spans, which, although rare, can sometimes be unavoidable. This study introduces a novel analytical method, rooted in the energy method and cable theory, for computing the static deformation and natural frequency of long free-span underwater pipelines. We conducted a comprehensive verification of our proposed method by comparing its outcomes with those of 212 finite element analysis simulations. The results reveal excellent predictions for long spans. However, for shorter spans, traditional methods remain more accurate. Additionally, we explored the influence of pipeline’s diameter, thickness, and boundary conditions on both static displacement and frequency, providing valuable insights for design considerations. We found that the boundary conditions’ impact on the fundamental frequency becomes negligible for long spans, with up to a 10% difference between pinned–pinned and fixed–fixed conditions. In essence, this research offers a vital enhancement to the existing DNV guidelines, becoming particularly beneficial during the preliminary design phases of pipelines with L/D ratios exceeding 140.

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Section: Determination Of Natural Frequency Of a Long Free-spanning P...mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

An Analytical Expression for the Fundamental Frequency of a Long Free-Spanning Submarine Pipeline

Phuor,

Trapper,

Ganz

2023

Mathematics

View full text Add to dashboard Cite

show abstract

“…Experimental verification was conducted to validate the accuracy of the proposed method [10]. Several studies have demonstrated that both the top tension and internal fluid play crucial roles in influencing the dynamic response of the riser [11][12][13][14]. Yuan et al utilized the force decomposition model to establish the equations of motion for the riser and investigated the effects of vortex force, relative inertia force, and Coriolis force induced by the internal fluid on the riser [15].…”

Section: Introductionmentioning

confidence: 99%

Dynamic behavior of risers under nonlinear oceanic environmental loading

Xu,

Yuan,

Luo

et al. 2023

J. vibroeng.

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The riser system acts as the vital link between the subsea blow-out preventer and the drilling platform. Affected by factors like top tension and marine environmental forces, the riser undergoes deformation and wear, carrying the risk of environmental pollution and financial losses upon failure. Hence, this study examines the riser's dynamic response to marine environmental loading. Initially, the motion differential equation for the riser system under the influence of nonlinear oceanic load is deduced using the principle of minimum potential energy and the variational method for extremum seeking. Subsequently, a nonlinear wave-current load model based on the Morrison equation is established, and the resulting equation is discretized into a finite element model using third-order Hermite interpolation function and the Galerkin weighted residual method. Finally, the dynamic response of the riser is scrutinized employing the Newmark numerical integration method. The study also investigates the impact of both oceanic environmental parameters and drilling parameters on the riser’s dynamic behavior. Comparative analysis of the numerical results reveals that the maximum displacement of the riser occurs at the middle section, whereas the maximum deflection angle is observed at the end of the riser. The periodicity of the deflection angle response is influenced by the position of the riser, showing a trend of decreasing and then increasing from the middle section towards the ends. Notably, the top tension and the velocity of the surface tidal current significantly affect the dynamic behavior of the riser. The findings of this study provide a theoretical foundation for the assessment of riser reliability and the determination of operational parameters.

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Effects of cavitation on vortex-induced vibration of a flexible circular cylinder simulated by fluid-structure interaction method

et al. 2022

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Investigating cross-flow vortex-induced vibration of top tension risers with different aspect ratios

Cited by 8 publications

References 29 publications

An Analytical Expression for the Fundamental Frequency of a Long Free-Spanning Submarine Pipeline

An Analytical Expression for the Fundamental Frequency of a Long Free-Spanning Submarine Pipeline

Dynamic behavior of risers under nonlinear oceanic environmental loading

Effects of cavitation on vortex-induced vibration of a flexible circular cylinder simulated by fluid-structure interaction method

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