双分裂导线次档距振荡的气动力模型与解析

Aerodynamic Model and Mathematic Expression of Twin-Conductors’ Subspan Oscillation

次档距振荡是分裂导线特有的一种振动现象,由前端导线的尾流引起后端导线的振动。导线绕流其实质是流体的圆柱绕流,通常条件下将在尾流区产生卡门涡街。本文建立了一种理想的卡门涡街模型,在对该模型进行数学解析的基础上,提出了双分裂导线中后端导线绕流的准定常气动力数学表达式,并通过与经典风洞实验所得的气动力系数对比修正该表达式的相关系数,为解决导线绕流问题提出了新的方法。

Subspan oscillation is a unique phenomenon to split conductors, in which the flowing of upward conductor causes downward conductor’s vibration. The essence of the flowing around a conductor is the flowing around a cylinder. Karman vortex street will emerge downstream usually. With ahypothetical modal of Karman vortex street being set up in this paper, a mathematical expression of its quasi-steady drag and lift is founded on the base of the analysis of this modal. Then relative coefficient in aforementioned is amended according to the data acquired from wind tunnel testing. Thus a new idea is proposed to solve the question of the flowing around conductors.