Vortex-induced Vibration Research Articles

Optimizing vortex-induced vibration suppression in π-shaped girders using wind tunnel testing and CFD analysis

This investigation meticulously explores the vortex-induced vibration (VIV) characteristics in Π-shaped girders within long-span cable-stayed bridges, presenting novel VIV mitigation techniques. Employing detailed wind tunnel evaluations of a 1:50 scale model alongside computational fluid dynamics (CFD) analyses to model the two-dimensional flow around the girder, this study reveals the formation and shedding of vortices behind the railings and main steel girder, which significantly contribute to VIV in such structures. The introduction of horizontal splitter plates, one m in width, in conjunction with two-m-wide V-shaped guide vanes, was found to substantially reduce the VIV amplitude of the Π-shaped girder, minimizing vortex generation on the deck’s sides and dramatically reducing the maximum vertical VIV amplitude from 208.75 mm to only 5.56 mm. CFD simulations confirm the effectiveness of these measures in suppressing Karman vortex street formation, thereby significantly improving downstream airflow characteristics. These findings offer pivotal insights for the advancement of bridge design and the proactive management of VIV, showcasing the potential of integrated aerodynamic modifications to enhance structural resilience and performance.

Numerical investigation of synthetic jet effects on vortex-induced vibrations in tandem circular cylinders

ABSTRACT The influence of symmetric synthetic jets, on the upstream cylinder's (Cylinder 1's) leeward side on VIVs of tandem circular cylinders, was numerically investigated at Re = 150, m* = 2.0. The amplitude responses, frequency responses, hydrodynamic forces and wake patterns were analysed in the reduced velocity U* range of 3.0–14.0. The results indicated that synthetic jets with sufficient momentum coefficients (C u = 2.0 and 4.0) could suppress transverse oscillations of both cylinders, resulting in a symmetric +2S wake pattern. While the standard deviations of lift coefficients for Cylinder 1 decreased accordingly, the time-averaged drag coefficients of both cylinders didn't always follow suit. Complex wake patterns, including 2S + 2S, 2P + 2S, 2P + 2P, 2(P + S) + 2P and 2(P + S) + 2(P + S), were observed when synthetic jets can't dominate Cylinder 1's vortex shedding. Galloping responses of both cylinders can also be initiated.

A Systematic Review of Techno-Economic, Environmental and Socioeconomic Assessments for Vibration Induced Energy Harvesting

There is a growing need to ensure the resilience of energy and water systems through digitalization, retrofit these systems for cleaner energy systems, and protect public safety in terms of water quality. This resilience requires a reliable power supply that could be provided by harnessing unexploited energy hidden in the current water infrastructure through the deployment of vortex-induced vibration energy harvesters. Therefore, being able to understand the feasibility of deploying these devices across technical, socioeconomic and environmental scales could further enhance successful deployment and integration of these devices. This paper aims to provide a systematic review investigating the development of energy harvester technologies to understand the key methods used to assess their application feasibility. This study used the PRISMA guidelines, and 139 articles were reviewed and synthesized. The trends were visualized, illustrating the current direction in energy harvesting development and application and methods used to assess the feasibility of these devices and technology. The majority of the reviewed studies focused on technical feasibility, design configuration, limitation, and identification of the most optimal application environment. The results revealed a huge opportunity for energy harvesters, especially as a power supply for monitoring sensors. Nevertheless, the results also identified a knowledge gap when it comes to assessing the overall application feasibility of energy harvesting as most studies currently neglect economic feasibility, environmental impacts, social aspects and energy resilience. Assessment tools will help fill this knowledge gap by identifying the key barriers and benefits gained from integrating this technology into existing energy systems and water systems.

Aeroelastic analysis of non-conventional and slender suspension bridges

The aim of this study was to investigate the dynamic effects of wind actions on bridge cross sections, with a goal to propose design charts for non-conventional and slender bridge decks. An eigenvalue analysis was conducted first and the results were validated experimentally. Subsequently, aeroelastic analysis of the bridge deck section was performed. This analysis encompassed the analytical method adhering to the Eurocode and computational fluid dynamics simulations. Both methodologies indicated that the bridge was susceptible to vortex-induced vibrations. To mitigate these vibrations, wind noses provide better stability than the currently used guide vanes. The effect of changing deck width was also studied. Wider and more streamlined sections displayed better aeroelastic performance. The study also revealed that the Eurocode overestimates the derivatives of aerodynamic moment coefficient by 53% to 93%. Consequently, optimized charts are proposed to enhance the accuracy of torsional divergence and flutter speed calculations, facilitating the safe and efficient design of such bridges.

Multi-directional and multi-modal vortex-induced vibrations for wind energy harvesting

A conventional vortex-induced vibration (VIV)-based energy harvester is typically restricted to capturing wind energy from a very limited range of wind directions, making it inefficient in varying wind conditions. This Letter proposes a tri-section beam configuration for VIV-based piezoelectric energy harvester to enable harnessing wind energy from varying incident angle with different vibration modes being triggered. The finite element analysis investigates the tri-section beam harvester's mode shapes and natural frequencies. A wind tunnel experiment is conducted for a comparative study of the energy output performance of the harvesters with straight and tri-section beams. The findings show that the proposed harvester with the tri-section beam can efficiently capture wind energy from a much wider range of incident angles, as opposed to the specific limited directions of its counterpart with the straight beam. The proposed harvester can also widen the lock-in speed range with a higher bending mode being triggered and achieve the optimal output power of 1.388 mW when the proposed harvester works in the second mode at a higher natural frequency, superior to that of its counterpart (0.386 mW) that can only work in the first mode. The proposed configuration sheds light on developing multi-directional and multi-modal VIV-based energy harvesters adapted to wind conditions in natural environments.

An Experimental Study on Vortex-Induced Vibration Suppression of a Long Flexible Catenary Cable by Using Vibration Dampers

In this paper, an experimental study is conducted to investigate the effectiveness of vibration dampers in suppressing vortex-induced vibration in a long, flexible catenary cable with a low mass ratio. The dampers, consisting of two small, symmetric, lightweight pipes clamped to the cable, are sparsely deployed along the cable to shape the vibration characteristics. The experimental results demonstrate that dampers significantly reduce the vibration amplitude by up to 60% and axial tension by up to 61% at high flow velocities, effectively suppressing the cable vibration in perpendicular flow. In addition, it is observed that the in-line and cross-flow vibration frequencies are approximately equal when the dampers are applied. This behavior contrasts with the conventional undamped catenary cable, where the in-line vibration frequencies are double those of the cross-flow frequencies.

A Review on the Recent Process of Lazy Wave Risers

Lazy wave risers (LWRs) are designed with equidistant buoyancy blocks attached in the lower half of the riser, allowing the riser to take on an arch shape under the buoyancy forces provided by buoyancy blocks. This arch configuration can provide flexibility to the LWR arrangement and effectively isolate the dynamic responses between the offshore floating structure and the riser’s touchdown zone (TDZ). Its design and application aim to address the issues of dynamic response and fatigue damage that traditional steel catenary risers (SCRs) face in deep water and complex marine environments. Given that research on the LWRs in the field of ocean engineering is not sufficiently abundant, the structural characteristics, hydrodynamic loads, global responses, fatigue damage assessment, and structural optimization progress of LWRs are systematically reviewed in this paper to provide references for researchers in related fields. Among these topics, the global response of LWRs is the main point of this review. This section details the theoretical analysis and numerical modeling methods employed in the study of LWRs’ global response, explores the research advancements in the vortex-induced vibration (VIV) related to LWRs, and discusses corresponding experimental studies. Finally, the installation, transfer, and repair processes of LWRs are investigated. Additionally, the importance of leveraging advanced technologies from other fields and combining them with current advanced algorithms is emphasized in efforts to assess fatigue damage and optimize the structures of LWRs, ultimately achieving complementary advantages.

Improvement of mixing performance in laminar micromixers utilizing vortex-induced vibration of two circular cylinders

Micromixers have found extensive applications in various fields such as engineering, biomedicine, medical and chemistry. The utilization of vortex-induced vibration (VIV) of bluff bodies can greatly enhance fluid mixing in micromixers. This study focuses on numerically investigating the interaction between vortex-induced vibration of two cylinders, labeled Cyl-S (stationary cylinder) and Cyl-V (vibrating cylinder), and the mixing performance of micromixers. Specifically, the study examines the effects of spacing ratio (S/D) and vibration system configurations (Cyls-S+S, Cyls-S+V, and Cyls-V+V) on vibration response, near-wake structure, mixing concentration, and mixing index. The results indicate that the spacing ratio directly influences the vibration response of the cylinders, thereby significantly impacting the mixing performance. For the Cyls-V+V configuration, the downstream cylinder exhibits a considerably higher vibration amplitude compared to the upstream cylinder. Increasing the S/D ratio substantially improves the mixing effect in the Cyls-S+S configuration. For the Cyls-S+V and Cyls-V+V configurations, the enhancement of mixing due to VIV is particularly noticeable when S/D ratios of 2 and 3 are employed. The mixing index for Cyls-V+V is higher than that for Cyls-S+V within the range of 3 ≤ U⁎ ≤ 5 (where U* represents the reduced velocity). At a reduced velocity of U⁎ = 4 for Cyls-V+V, the optimal mixing indexs are found to be 0.77 (S/D = 2), 0.76 (S/D = 3), 0.78 (S/D = 4), and 0.77 (S/D = 5), respectively. However, when U⁎ = 6–10, the mixing index decreases due to the vibration of the cylinder is suppressed. Additionally, the Cyls-V+V configuration exhibits a significantly higher pressure drop within the flow channel compared to the Cyls-S+V configuration.

Flow-induced vibrations of an equilateral triangular prism at subcritical Reynolds number

It has been well known that the shear layers behind a prism at subcritical Reynolds number (Re) remain persistently stable. However, potential response of an elastically mounted non-circular prism at subcritical Re is still open. In this study, we numerically investigate the flow-induced vibrations of an equilateral triangular prism at subcritical laminar flow using the immersed boundary method. The prism is allowed to vibrate only in the transverse direction. It is found that the prism vibration could be excited and sustained at subcritical Re due to the instability triggered by the prism's movability. Within angles of attack α = 0°–60°, the triangular prism experiences three responses: i.e., vortex-induced vibration (VIV) at α = 0°–30°, large-amplitude vibration at α = 37.5°–46.5°, and galloping at α = 47.5°–60°. The characteristics of vibration amplitude, frequency, and dependence of fluid forces on reduced velocity and α are investigated. Eight different wake modes exist behind the prism, i.e., one stable mode, two shear layer modes, and five vortex shedding modes. In the VIV regime, the 2S mode (2 single vortices per vibration cycle) is the only vortex shedding mode, while the vortex shedding mode with more than two vortices is unique in the other two regimes. In the end, we discuss (i) the influences of Re and mass ratio and (ii) prediction of the galloping instability using quasi-steady analysis. It is found that three different response regimes are noticed, although their characteristics are strongly affected by the two factors. Quasi-steady approach could provide a reasonable prediction of the emergence of galloping instability for non-circular prism.

Viscoelasticity in the flow suppresses one- and two-degree-of-freedom vortex-induced vibrations of a cylinder

Viscoelasticity in the flow suppresses one- and two-degree-of-freedom vortex-induced vibrations of a cylinder

Unlocking multidirectional and broadband wind energy harvesting with triboelectric nanogenerator and vortex-induced vibration of sphere

Unlocking multidirectional and broadband wind energy harvesting with triboelectric nanogenerator and vortex-induced vibration of sphere

Investigation of the Influence of Spoiler and Maintenance Track on Second-Order Heaving Vortex-Induced Vibration

To improve the guidance for the wind tunnel test, this study initially conducted thorough research on the wind environment at a coastal bridge site to ascertain the characteristics of the wind parameters varying along the bridge span. Subsequently, the measured results were utilized to steer wind tunnel test research, focusing on analyzing the influence of the spoiler and maintenance track on the second-order heaving vortex-induced vibration of the flat steel box girder. This investigation uncovered two distinct distributions in the angle of attack along the span: bimodal distribution and asymmetric unimodal distribution. The angle of attack of the incoming flow was primarily concentrated within ±5°. Both the two-side and the windward spoiler were found to exert similar effects on the second-order heaving vortex-induced vibration, primarily impacting the second lock-in region. Furthermore, the outer maintenance track could effectively suppress the vortex-induced vibration, while the spacing of the inner maintenance track significantly affected the vortex-induced vibration at high wind speeds.

Simulation and Experiments on Optimization of Vortex-Induced Vibration Power Generation System Based on Side-by-Side Double Blunt Bodies

In order to improve the utilization efficiency of converting low-flow current energy into electric energy for Reynolds number 10,000 ≤ Re ≤ 40,000, this paper proposes a vortex-induced vibration power generation system based on a side-by-side double blunt body. In this system, the side-by-side double blunt body structure is used in the current energy capture part to enhance the collection of low-flow current energy; the permanent magnet linear motor is used in the electric energy conversion part to improve the efficiency of electric energy conversion; and a laboratory device is constructed for testing. The effects of the blunt body structure parameters and the center spacing ratio on the energy harvesting performance of the system are qualitatively explained by constructing a simulation model. Compared with the single blunt body energy capture structure, the side-by-side double blunt body structure increases the vibration amplitude by 1.04 times and the lift by 1.14 times at the center spacing S/D = 2.4. Meanwhile, energy harvesting can be realized at a lower flow velocity, increasing the vortex-induced vibration’s energy capture range. Finally, the power generation system was experimentally verified in the laboratory, and the results showed that the vibration amplitude of the double blunt body structure was increased by 1.12 times compared to the single blunt body. The maximum output power of the generator is 10.55 W when the water velocity is 0.7 m/s. The energy conversion efficiency of the power generation system can reach a maximum of 52.93%, which is 12.33% higher than that of a single blunt body structure, which proves that the system has a higher power conversion efficiency than that of a conventional single conversion system.

Numerical analysis of vortex-induced vibration of deepwater drilling riser based on Van der Pol wake oscillator model

Coupled equations of the dynamic model and the Van der Pol wake oscillator model are solved by the central finite difference method for the deepwater drilling riser. The vortex-induced vibration (VIV) response and fatigue life of the riser are calculated and the model validation is performed by comparing with the published experimental and simulation results. The effects of the top tension, current flow velocity, flow velocity profile, internal flow velocity as well as the installation of buoyancy modules on the VIV are discussed. Dynamic response and fatigue life of the riser under In-Line (IL) and Cross-Flow (CF) VIV are preliminarily analyzed. The results show that the VIV of the riser has multiple modes and exhibits a mixed behavior of standing waves and traveling waves. With the increase of top tension and flow velocity profile coefficient, the order of the VIV dominant mode and the peak values of the root mean square (RMS) of VIV displacement decrease, and the fatigue life of the riser is extended. With the increase of current flow velocity, the order of the VIV dominant mode increases and the riser fatigue life decreases. The effect of internal flow velocity on the riser VIV is neglectable. The installation of buoyancy modules can improve the riser stress state and extend the fatigue life. Compared with the CF VIV model, the calculated minimum fatigue life of the riser is extended under the IL and CF coupled VIV model due to the decrease of bending moment and the changing position of fatigue weak point.

Deep learning-based approach for identifying vortex-induced vibrations in stay cables

Due to variations in wind speed profiles along the length of bridge stay cables, vortex-induced vibrations (VIV) exhibit multimodal characteristics, presenting challenges for VIV identification. Currently, the VIV identification is concentrated on the stable stage of VIV, lacking an available early warning system for detecting the initial developing stage of VIV. In this study, a deep learning-based approach that integrates energy distribution ratio features derived from frequency band wavelet packet decomposition to recognize VIV of stay cable was proposed. Firstly, vibration characteristics induced by vortices in cable-stayed bridges were analyzed based on field monitoring data from the bridge health monitoring system, aiming to propose suitable feature indicators for VIV identification. Secondly, using root mean square as label classification, a deep learning model was constructed, incorporating convolutional neural networks, long short-term memory networks, and attention mechanisms. Finally, four different stages in the evolution of stay cables VIV were identified utilizing field monitoring datasets to analyze the optimal parameter. Meanwhile, effective early warning recognition was achieved through the classification and recognition of confusion matrix. This study provides technical support for early warning systems and structural condition assessment concerning bridge stay cable VIV.

Deep learning-based automated identification on vortex-induced vibration of long suspenders for the suspension bridge

Large amplitude vortex-induced vibration (VIV) of long suspenders, caused by vortex-shedding and wake flow, will decrease the service life of high-strength wires and its anchorage systems, hence listed as an essential monitoring indicator of the structural health monitoring system in the suspension bridges. Traditionally, a static vibration amplitude limitation is usually predefined and used to identify VIV from continuously monitored acceleration data of bridge suspenders. Due to the complexity of the starting vibration of the suspenders, it may not be able to flexibly adapt to the suspenders VIV under different conditions. In addition, transient but significant vibration events may not be captured since it relies only on static vibration amplitude limits without considering the temporal information of vibration. To address the above-mentioned issues, a novel framework to autonomously identify the suspenders VIV is proposed using the multimodal fusion techniques with deep neural networks. The main contributions of the methodology are: i) by calculating the wind field and vibration characteristic, two vibration response parameters are identified as indexes for the identification of suspenders VIV based on the significant difference method of big data analysis; ii) Two different modal information of time history images and power spectral density (PSD) sequences are used as inputs to the convolutional neural network (CNN) and bidirectional long short-term memory (BiLSTM) to extract the suspenders vibration response features from the time and frequency domain perspectives, respectively; and iii) The multimodal information is concentrated and enhanced by the multi-head attention (MHA) mechanism to achieve automated identification of the suspenders VIV. The proposed framework is validated with data collected from a full-scale long-span suspension bridge in comparison with the base model. The results show that the proposed framework can efficiently identify the full-cycle development process of the suspenders VIV. This study provides a convenient strategy for suspenders VIV identification, which can be used for bridge management and vibration mitigation device design.

Numerical Study of Vortex-Excited Vibration of Flexible Cylindrical Structures with Surface Bulge

This study conducted numerical simulations of three-dimensional vortex-induced vibrations (VIV) on cylindrical bodies with various surface protrusion coverage rates, systematically investigating the impact of coverage and protrusion height on the vibrational response of flexible cylinders. The fluid forces on the surface of the riser were resolved using the finite volume method, while the structural forces were solved with the finite element method. A strongly coupled approach was employed for iterative updates between the flow field and structural field data, achieving a bidirectional flow–structure coupling simulation of VIV in a marine environment. The study further explored the performance of surface protrusions in suppressing VIV and considered protrusion heights of 0.1 times the cylinder diameter (0.1D) under coverage rates (CR) of 0%, 10%, 20%, 30%, and 40%, as well as seven different protrusion heights of 0.05D, 0.1D, and 0.15D at a 20% coverage rate. The mechanism of VIV suppression by surface protrusions was identified as altering the separation point of the shear layer and the frequency of vortex shedding through the vortices formed between the surface protrusions. It was found that a 20% coverage rate with a protrusion height of 0.01D (CR20) effectively suppressed the VIV of the cylinder, showing the best performance in VIV suppression, with an efficiency of 30.04%. These results provide a theoretical basis for designing more efficient VIV suppression devices and contribute to enhancing the resistance of marine structures against vortex-induced vibrations.

Numerical Study of Vortex-Induced Vibration Characteristics of a Long Flexible Marine Riser

In ocean engineering, interactions between ocean currents and risers lead to regular vortex shedding on both sides of the riser, causing structural deformation. When the frequency of vortex shedding approaches the natural frequency of the structure, resonance occurs, significantly increasing deformation. This phenomenon is a critical cause of riser failure. Therefore, the dynamic response of flexible risers to vortex-induced vibrations (VIV) is crucial for their structural safety. This paper employs the finite-volume method to integrate over control volumes to solve for forces, such as pressure and shear stress, on the surface of the riser, while the finite-element method discretizes the continuous structural body into elements and nodes to solve for structural displacements and stresses. A strongly coupled method is utilized at each timestep to iteratively transfer load-displacement data between the fluid and structural fields, updating the boundary conditions of the fluid domain to achieve a bidirectional fluid–structure interaction simulation of vortex-induced vibrations in a seawater environment for flexible risers. The study finds that the three-dimensional flexible riser exhibits multi-frequency vibration phenomena and broadband vibration response characteristics under high flow velocity conditions. As the flow velocity increases, the vortex-shedding mode is observed to transition from the simple two single (2S) mode to the more complex pair + single (P + S) and two pair (2P) modes. In addition, the stiffness at the ends is enhanced by the fixed boundary conditions, and the coupling between the natural frequency of the ends and the vortex-shedding frequency triggers complex vortex-shedding phenomena in these regions. At higher flow velocities, these boundary effects result in more complex vortex-shedding modes and stronger vibration responses at both ends of the riser.

Vortex-Induced Vibration Performance Analysis of Long-Span Sea-Crossing Bridges Using Unsupervised Clustering

Vortex-induced vibration is a type of wind-induced vibration occurring frequently in large-span sea-crossing bridges under relatively low wind speeds, posing a threat to the structural fatigue performance and driving comfort. Identifying the instantaneous occurrence moments of vortex-induced vibration is a prerequisite for establishing a data-driven prediction model for vortex-induced vibration, and it is of great significance for the monitoring and early warning of vortex-induced vibration performance in bridges. To automatically detect the occurrence moments of vortex-induced vibration and establish a correlation model between vortex-induced vibration amplitude and environmental factors, this study proposes a fuzzy C-means clustering-based classification method. In order to detect the occurrence moments of vortex-induced vibration more finely, only short-term or even instantaneous structural vibration indicators were selected and transformed for distribution as clustering features. The entire detection process could be carried out unsupervised, reducing the manual cost of obtaining vortex-induced vibration information from massive monitoring data. Finally, actual vortex-induced vibration test data from a certain overseas bridge was utilized to verify the feasibility of this method. Based on the classification results, the correlation between vortex-induced vibration amplitude and environmental variables was determined, providing valuable guidance for predicting vortex-induced vibration amplitudes.

Response control of chimneys using tuned mass damper, multi-tuned mass damper and tuned mass inerter system

Growing industry and shifting environmental regulations have made chimneys taller and more flexible, thus making them susceptible to wind forces. Consequently, it becomes necessary to analyze the chimney for undesired wind force causing vortex induced vibration (VIV) and to enhance their performance by the implementation of appropriate countermeasures. In this study, three passive control devices, namely, tuned mass inerter system (TMIS), tuned mass damper (TMD) and multi-tuned mass damper (MTMD), are used to control the VIV of high-rise chimneys. The TMIS comprises a mass element, spring, damper, and inerter subsystem. The MTMD is distributed over the top one-third height of the chimney. The three control devices control the response of the chimneys under random vortex induced forces, and their relative performances are evaluated. The modal spectral analysis and Genetic Algorithm are employed to establish a method for optimizing the damper-structure system for VIV control. The response analysis duly considers the effect of the nonlinear aero-elastic effect. The novelty of the paper lies in the application of TMIS for chimney subjected to vortex induced vibration and comparing its results with other traditional dampers (TMD and MTMD) for the three chimneys of height 120 m, 210 m, and 360 m of varying diameter, taken as illustrative examples. In addition, the study examines the impact of different mass ratios and the mass of the inerter on chimneys. For the three chimneys considered, it is observed that the performance of the TMD is best among the three control techniques adopted. For the tallest chimney (360 m), all three control devices display an optimum mass ratio for which the response reduction is maximum. The performance of the TMIS improves with the increased height of the chimney.