Study on Wind Load Distribution and Aerodynamic Characteristics of a Yawed Cylinder

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.