Aerodynamic forces and galloping instability for a skewed elliptical cylinder in a flow at the critical Reynolds number

作者：Ma, Wenyong^*; Liu, Qingkuan; Du, Xiaoqing^*; Liu, Xiaobing

来源：Fluid Dynamics Research, 2017, 49(4): 045509.

DOI：10.1088/1873-7005/aa7704

• elliptical cylinder
• critical Reynolds number
• skew flow
• aerodynamic force
• galloping instability

The mechanism of large-amplitude aeroelastic vibrations of cylindrical bodies in the critical Reynolds number range are still unclear. This study concerns the aerodynamic forces acting on elliptical cylinders and the induced galloping instability resulting from skew flows (i.e., the direction of the flow is angled 0 degrees-45 degrees with respect to the central axis of the cylinder) for Reynolds numbers in the range of 37-235 k. The effects of the critical Reynolds number and the skew angle on the aerodynamic forces and the galloping instability are investigated with pressure wind tunnel tests. In all of the cases investigated in the present study, a sharp decrease in the lift coefficient with increasing angle of attack and a reduction in the drag coefficient at the critical Reynolds number could be responsible for the galloping instability. Variations in the torque coefficient leads to a torsional aerodynamic instability at the critical Reynolds number. Furthermore, the skew flow cause a critical flow state at lower Reynolds numbers. One possible reason for this behavior is that the longer effective cross section allows the flow to reattach.

• 出版日期2017-8
• 单位上海大学