The flow mechanism around a yawed cylinder is highly complex. While previous research has confirmed the limitation of the Independence Principle at high yaw angles, the specific flow phenomena beyond 20° yaw remain poorly understood, particularly concerning the spanwise development of the critical regime and the mechanism behind asymmetric surface pressure. Most studies have focused on spatially averaged forces or specific angles, lacking a systematic investigation of the inherent flow characteristics in the intermediate region of finite-length cylinders. To bridge this gap, the present study conducts a detailed wind tunnel test on a yawed cylinder across a wide range of yaw angles (0–60°). By analyzing the pressure distribution and aerodynamic forces in the mid-span region, this study yields the following core findings of universal significance: (1) As the yaw angle increases, the critical flow regime in the intermediate section occurs prematurely. This leads to a decrease in the Reynolds number at which the critical region begins, resulting in the formation of separation bubbles and consequent localized negative-pressure zones on either the upper or lower windward surface of the cylinder. (2) When the yaw angle β ≤ 17.4°, the mean drag and lift in the middle region resemble those of a straight cylinder. However, as the yaw angle increases further, the drag coefficient decreases beyond a certain critical Reynolds number, which itself decreases with increasing yaw angle. (3) At β = 0°, the circumferential mean pressure distribution is symmetric about the cross-sectional axis and remains largely uniform along the span. High yaw angles disrupt this symmetry and uniformity, leading to complex three-dimensional flow structures. These findings have critical implications for the design of structures like inclined bridge towers and cables under oblique winds.

To investigate the wind-induced vibration of a single-axis solar tracker, this study employs a combination of rigid model pressure measurement wind tunnel tests and finite element calculations. This study addresses the critical gap of full-array wind-induced response analysis and provides region-specific dynamic amplification factor recommendations applicable to comparable tracker configurations. The wind load distribution on the solar tracker surface is obtained through rigid model pressure measurement tests; the natural frequency and mode of the solar tracker are determined via finite element calculations; and the wind-induced response of the solar tracker is computed by integrating the wind load and its self-vibration characteristics. At small tilt angles, a shielding effect is observed, with the wake region exhibiting a lower standard deviation of the torque coefficient than the windward region, whereas at large tilt angles, an amplification effect is observed, with the wake region exhibiting a higher standard deviation. The wind-induced vibration of the solar tracker is predominantly characterized by torsional vibration around the main axis, with larger torsional displacements observed in the end regions and the area between the two drive posts. Furthermore, recommended dynamic amplification factors are provided: 2.07~2.41 for the corner regions, 1.85~1.92 for the mid-span regions, and 1.98~2.23 for the end regions.

Due to its complex mechanism of action, the wind-resistant design of square cross-section structures against vortex-induced vibration (VIV) still presents significant challenges. The angle of the wind direction is an important factor affecting the VIV characteristics of square cylinders. A series of stationary model pressure tests were performed and an elastic supporting model was used in the present study. The effects of the wind direction angle on parameters corresponding to fluid–structure interaction were analyzed with reference to the Strouhal number, range of “lock-in”, amplitude, and aerodynamic forces. The Strouhal number of the square cylinder was greatest at a 16° wind direction angle. When the wind direction angle was 10°, the wind speed range of vortex-induced vibration (VIV) of the square cylinder was the greatest, and the corresponding value was the smallest when the wind direction angle ranged from 20° to 45°. Within the vibration interval, the extreme value of the amplitude was smallest when the wind direction angle was 10°, and the extreme value of the amplitude was greatest when the wind direction angle was 30°. The vibration state had a minimal influence on the mean lift coefficient and a relatively large influence on the mean drag coefficient.