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.

Due to the limitations of wind tunnel speed and size, achieving a model’s Reynolds number equal to the actual Reynolds number is challenging and may lead to discrepancies between experimental and actual results. To investigate the effects of the Reynolds number on the aerodynamic forces and vortex-induced vibration (VIV) characteristics of a streamlined box girder, wind tunnel tests were conducted to study the variations in aerodynamic forces and surface pressures on the static main beam, as well as the VIV response and time–frequency characteristics of the aerodynamic forces on the dynamic main beam, as the Reynolds number varied. The results indicate that in static tests, as the Reynolds number increases, the drag coefficient of the main beam decreases, the lift coefficient slightly increases, and the pitching moment coefficient remains almost unchanged. The root mean square (RMS) values of the wind pressure coefficients show a significant Reynolds number effect, with values generally decreasing as the Reynolds number increases. In free vibration tests, as the Reynolds number increases, the onset wind speed of VIV increases from 14.35 m/s to 16.03 m/s, the maximum amplitude decreases from 0.076 to 0.004, and the VIV lock-in range narrows. The dynamic pressure results indicate that as the Reynolds number increases, the RMS values of the wind pressure coefficients decrease. At some measurement points, the dominant frequencies of the fluctuating pressure amplitude spectra deviate from the corresponding VIV frequency, and the correlation and contribution coefficients between the local aerodynamic forces and the overall vortex-induced force (VIF) decrease. These changes may explain the reduction in the VIV amplitude with an increasing Reynolds number. The motion state of the main beam has a minimal effect on the mean wind pressure coefficients and their Reynolds number effect, whereas it has a more significant effect on the RMS values of the pressure coefficients.

Equilateral-triangular arrangements of three-cylinder systems and rigid connection measures are common in engineering. In this paper, three cylinders in three equilateral-triangle arrangements with spacing ratios L/D = 2, 4, and 6 at a Reynolds number Re = 200 are studied through a numerical simulation. The characteristics of vortex-induced vibration (VIV), aerodynamic force, and flow field are analyzed. The results show that the variation trends of the VIV responses in relation to the spacing ratio of the three rigidly coupled cylinders vary depending on different cases (case A, case B, and case C). The lock-in regions of d/D = 2 are significantly larger than those for the other spacing ratios. At this spacing ratio, the vibration amplitude in case A is smaller than that in other cases, which may be caused by the bifurcation between the lock-in region. The lock-in region for frequency corresponds to or is slightly less than the vibration region. In the late lock-in region, the vortex shedding frequency is several times higher than the natural vibration frequency for d/D = 2 in cases B and C. The wake changes obviously with the increase in spacing ratio. The wake appears as merging vortexes in the transverse directions at large reduced velocities for d/D = 2. The wake parallel vortex in the lock-in region excites large vibrations for d/D = 4 and 6 in cases B and C.

Rectangular cylinders with a ratio of 5:1 are extensively applied in engineering structures. Their aerodynamic characteristics, especially at high Reynolds numbers (Re), remain unclear. A series of force and wind pressure measurement tests at high Reynolds numbers are conducted on a 5:1 rectangular cylinder, with angles of attack ranging from 0° to 8°. The results show that the mean drag coefficient, moment coefficient, and Strouhal number exhibit significant Reynolds number effects, with noticeable angle of attack variations. At nonzero angles of attack, the probability density function curve of the lift coefficient changes from bimodal to unimodal with increasing Reynolds number, and the transition Reynolds number decreases with the increase in angles of attack. As the angle of attack increases, the vortex core on the upper surface moves downstream, whereas the opposite occurs on the lower surface. When the angle of attack equals or exceeds 2°, the reattachment point on the upper surface disappears. The effect of the Reynolds number on the mean pressure coefficient is negligible, whereas the fluctuating pressure coefficient at the rear of the upper and lower surfaces notably decreases with the increasing Reynolds number. The overall shape of the mean and fluctuating pressure coefficient distributions is unaffected by the Reynolds number. Vortex shedding dominates fluctuations of pressure on top and bottom surfaces. As the angle of attack increases, the pressure coefficient spectra minimum peak amplitude distribution shifts backward on the top surface and forward on the bottom, likely due to the movement of the vortex core.

Two-box edge girders are widely employed in bridge engineering owing to their superior mechanical properties. However, these girders are susceptible to vortex-induced vibrations (VIVs) due to their blunt configuration. Therefore, it is of great significance to study their VIV performance and specific suppression measures. Wind tunnel tests simultaneously measuring vibration and pressure and computational fluid dynamics (CFD) were performed to investigate the effects of sidewalk railing height and inclination angle on the VIV responses at different wind attack angles. Furthermore, surface pressure distribution, the relationship between distributed aerodynamic lift and the general vortex-excited force (VEF), and flow field characteristics were analyzed to elucidate the VIV suppression mechanism. Results indicate that vertical VIVs occur across all tested wind attack angles, with the most pronounced response observed at α = +5°. Both railing height and inclination angle significantly influence the VIV response, yet their influence patterns are different. Specifically, the VIV amplitude consistently increases with railing height across all wind attack angles, whereas the effect of the inclination angle varies depending on the wind attack angle. The leading and trailing edges of the upper surface and the trailing edge of the lower surface are identified as the critical areas responsible for VIV. The variations in fluctuating pressure coefficient and contribution value with railing configuration are generally consistent with those of the VIV response. Moreover, while the railing configuration does not alter the vortex shedding mode, it significantly modifies the vortex scale and pressure intensity, thereby resulting in distinct VIV responses.