Vortex-induced vibration characteristics of twin-box girder section in long-span bridge: A numerical evaluation method

Review of the excitation mechanism and aerodynamic flow control of vortex-induced vibration of the main girder for long-span bridges: A vortex-dynamics approach

This study investigated the vortex-induced vibration (VIV) characteristics of a proposed water-conveying truss pipeline cable-stayed bridge through wind tunnel tests. The experimental results indicated that both vertical bending and torsional VIV responses decreased as the wind attack angle increased. The vertical bending VIV behavior of the bridge was significantly influenced by the lateral spacing and relative height of the pipelines. Adjustments to these geometric parameters markedly affected the structural VIV response. Furthermore, computational fluid dynamics (CFD) was employed to analyze the flow field around the truss pipeline bridge. The results revealed that changes in the lateral spacing and relative height of the pipelines primarily altered the VIV performance by modifying vorticity distribution, separation point position, and other critical flow field parameters around the truss section. These findings underscore the importance of considering the effects of geometric parameters on VIV during the design of the truss section in pipeline bridges.

Experimental study on characteristics of vortex-induced vibration of a twin-box girder and damping effects

The lower semi‐open box (LSOB) girder is widely used in large‐span bridges due to its favorable stress performance and cost‐effectiveness. The vortex‐induced vibration (VIV) of the LSOB girder was studied by using a 1:55 section model wind tunnel test. The test results show that there are obvious vertical and torsional VIV intervals with significant amplitudes at each angle of attack with the damping ratios of about 0.35%. The CFD numerical simulations indicate that VIVs of LSOB girders are mainly induced by two types of vortices: one at the inclined webs of leeward wind nozzles and another at the upstream upper surfaces of the deck. Conventional aerodynamic vibration suppression measures, such as the lower central stabilizing plate and the guide vane at the gantry rail, demonstrate that the lower central stabilizing plate can reduce the VIV response at all wind angles of attack, decreasing vertical amplitude by 40%–50% and torsional amplitude by 10%–25%. Although adding a guide vane further optimizes the VIV performance, its effect is limited. Installing the lower central stabilizing plate helps redistribute vortices below the girder, transforming large vortices into smaller ones, most of which do not detach, thereby reducing vortex shedding intensity in the wake area. The bilateral guide vanes at the maintenance car track further weaken the wake vortices at the diagonal webs on the leeward side.

Effects of end condition and aspect ratio on vortex-induced vibration of a 5:1 rectangular cylinder

Ride comfort evaluation of stochastic traffic flow crossing long-span suspension bridge experiencing vortex-induced vibration

Given the significant influence of wave propagation on the airflow structures and aerodynamic behavior of sea-crossing bridge decks, understanding the effects of the dynamic wave boundary layer (WBL) on vortex-induced vibration (VIV) is crucial. This study proposes a numerical simulation framework to investigate how dynamic WBL impacts VIV characteristics of sea-crossing bridge decks. A wave-following mesh scheme with periodic boundary conditions generates homogeneous dynamic WBL airflows. These validated flow conditions are integrated into a two-dimensional unsteady Reynolds-averaged Navier–Stokes (URANS) simulation incorporating fluid–structure interaction to analyze the VIV response of a sea-crossing bridge deck. Simulation results reveal that the oscillatory wind field induced by waves alters vortex shedding and deck surface pressure distribution, thereby disrupting VIV onset conditions and reducing its amplitude. Specifically, as the deck approaches the wave surface, the influence of waves on the aerodynamic performance of the deck becomes more pronounced, leading to a reduction in VIV amplitude with decreasing deck-wave clearance. Notably, under wind speeds outside the VIV range, dynamic WBL induces forced deck vibrations. In such cases, deck vibration frequency and phase synchronize with wave motion, and reduced deck-wave clearance amplifies forced vibration amplitude.

Previous studies have shown that grooves can decrease the drag of a circular cylinder (Re = 4.8 × 103–1.2 × 105), suppress vortex-induced vibration and rain-wind-induced vibration, and have potential applications in reducing the drag and damping vibrations of stay cable structures. However, the aerodynamic performance of grooved circular cylinders at high Reynolds numbers (Re = 105–106) remains unknown. Therefore, a series of wind tunnel tests were performed on grooved cables, including measurements of surface pressure, vortex-induced vibration, and dry galloping. Various aerodynamic parameters (such as surface wind pressure distribution, aerodynamic forces, and the Strouhal number), vortex-induced vibration characteristics, and dry galloping characteristics were investigated, and the results were compared with those of standard cables. The results indicated that, relative to standard cables, the average drag coefficient of grooved cables is smaller at low Reynolds numbers, and the drag reduction effect is correlated with the number of grooves, with a maximum drag reduction rate of 47%. The drag reduction effect of the grooved cables gradually decreases as the Reynolds number increases, and the grooved cables stop exerting a drag reduction effect when Re > 3.1 × 105. Compared with standard cables, the circumferential average wind pressure of grooved cables is more stable with respect to the Reynolds number, and the Reynolds number effect is weaker. The maximum amplitudes of the vortex-induced vibrations and dry galloping of the grooved cables are lower than those of standard cables. The optimal suppression efficiencies of vortex-induced vibrations for 16- and 32-grooved cables are 96.0% and 52.0%, respectively, whereas those of dry galloping for these are 75.0% and 81.8%, respectively.

Abstract: Bridge vortex induced vibration (VIV) is a resonance phenomenon caused by the periodic shedding of vortices generated by natural wind passing through bridges. Bridge VIVs will not only cause fatigue damage to the structures but also affect driving safety for the passing vehicles. With the popularization of structural health monitoring (SHM) systems, machine learning technology is widely used in the field of vortex induced vibration identification for long-span bridges, due to its intelligence, real-time performance, and sensitivity to data. However, although traditional machine learning algorithms can identify the VIV based on the response data history of long-span bridges collected by SHM systems, they are difficult to apply to bridges which do not have historical vortex induced vibration data. Therefore, this paper proposes an adaptive transfer learning method for identifying VIV in the main girder of long-span suspension bridges. The proposed method can identify VIV without VIV history data of the target bridge. Results show that it can well identify VIVs at the earlier stage based on the SHM datasets of two long-span suspension bridges, verifying its effectiveness and generalization ability.

Experimental investigation of the vortex-induced vibration of tapered light poles

Vortex-induced vibration (VIV) is a typical nonlinear fluid–structure interaction phenomenon. Although the semi-empirical model is a theoretical and efficient manner, it is difficult to accurately predict the above nonlinear phenomena due to the incomplete mathematical expressions and uncertain parameters. In this article, the recursive radial basis function neural network (RRBFNN) is proposed to modify the typical vortex induced force (VIF) model. The RRBFNN VIF model was first constructed, and the dynamic equation for calculating VIV response was created, based on the significant nonlinear fluid–structure interaction characteristics of VIV. The aerodynamic forces of the two-edge box girders under various reduced velocities and vibration amplitudes were calculated via computational fluid dynamics (CFD) in order to obtain the mentioned VIF model parameters and verify the efficacy of several RRBFNN learning methods. Ultimately, the amplitude of vortex-induced vibration was predicted using the earlier-mentioned effective training method, and the aerodynamic decoupling method was used to investigate the influence of multiple order aerodynamic forces on the vortex-induced vibration response. As a result, the RRBFNN accurately simulates the aerodynamic force in the time domain and frequency domain. The orthogonal least squares (OLS) and exponential basis function are well-suited to the RRBFNN VIF model. The decisive factor of VIV is the fundamental frequency signal in the aerodynamic force. The second harmonic wave can significantly affect the VIV amplitude, while the influence of the third harmonic wave can be ignored.

Vortex-induced vibration (VIV) has been occasionally observed on a few long-span steel box-girder suspension bridges. The underlying mechanism of VIV is very complicated and reliable theoretical methods for prediction of VIV have not been established yet. Structural health monitoring (SHM) technology can provide a large amount of data for further understanding of VIV. Automatic identification of VIV events from massive, continuous long-term monitoring data is a non-trivial task. In this study, a method based on the random decrement technique (RDT) is proposed to identify the VIV response automatically from the massive acceleration response without manual intervention. The raw acceleration data is first processed by RDT and it is found that the RDT-processed data show different characteristics for the VIV response and conventional random response. A threshold based on the coefficient of variation (COV) of peak values of processed data is defined to distinguish between the two kinds of responses. Both random vibration and VIV for a three-DOF (degree-of-freedom) mass-spring-damper system are obtained by numerical simulation to verify the proposed method. The method is finally applied to the Xihoumen suspension bridge for identifying VIV response from three-month monitoring data. It is shown that the proposed method performs comparably with the method of novelty detection. A total of 60 VIV events have been successfully identified. Vortex-induced vibrations for the second to ninth vertical modes with modal frequency within 0.1~0.5 Hz occurs at wind velocity 5–18 m/s, with wind direction nearly perpendicular to bridge axis. Amplitude of VIV generally decreases with increase of wind turbulence intensity; however, noticeable VIV amplitude are still observed for turbulence intensity up to 13% in some cases.

The interfering characteristics of vortex-induced vibration (VIV) responses for tandem double risers under the recently discovered bidirectionally sheared flow are unclear. To reveal the interfering VIV characteristics in bidirectionally sheared flow, a rotating test rig was built to simulate bidirectionally sheared flow in the ocean basin. A series of VIV experiments for two scaled riser models were carried out, which included a single riser and tandem double risers with two different center-to-center spacing (3D and 5D). Then the modal superposition method was used to reconstruct the VIV displacements in cross-flow (CF) direction and the drag displacement. Furthermore, the drag coefficient was identified and analyzed. Results indicate that the VIV frequency of tandem double risers remains consistent at same spacing. When the reduced velocity (Vr) is in range of 5.0 to 18.0, the VIV amplitude of tandem double risers is basically same, but slightly smaller than that of the single riser. However, the VIV amplitude of riser 2 is significantly higher than that of riser 1 at Vr > 18.0. Moreover, it is found that the overall average drag coefficient in tandem double risers is lower than 1.38 of single riser, with values of 1.25 (S = 3D) and 1.33 (S = 5D) respectively.

Vortex-Induced Vibration (VIV) of flexible riser conveying severe slugging and straight flow in steady and oscillatory flows

Numerical study on the characteristics of vortex-induced vibrations of a small-scale subsea jumper using a wake oscillator model