串列双分裂导线屏蔽效应风洞试验研究

串列双分裂导线所受的风荷载中，处于下风向导线的阻力会受到上风向导线尾流脱落的影响。为研究分裂导线风荷载的屏蔽效应随风速和分裂间距的变化，在风洞中测量不同风速和分裂间距下3种工程常见导线的模型导线的整体阻力系数。同时，为了检验模型导线对真型导线模拟的精确性，测量了1种真型导线的阻力系数并进行比较。试验发现，模型导线对真型导线的模拟具有足够的精确性。随着分裂间距的增大，双分裂导线中下风向导线的阻力系数以及整体的阻力系数增大，但是均较现行规范给定值明显减小。随着风速的增大，双分裂导线的整体阻力系数先减小后增大，但是在各风速下，均较单根导线阻力系数明显降低。我国现行规范对于多分裂导线阻力系数的取值偏高，可以通过考虑屏蔽效应的有利影响合理地降低多分裂导线整体阻力系数的取值。

Wind Tunnel Test on Shielding Effect of Serial 2-Bundled Conductors

In the wind loads on serial 2-bundled conductors， the drag force of the leeward conductor can be influenced by the vortex shedding of the windward conductor. In order to investigate the wind load shielding effects of serial 2-boundled conductors with the variation of wind velocity and bundle spacing， the overall drag coefficients of three types of model conductors were tested in wind tunnel under different wind velocity and bundle spacing. Meanwhile， the drag coefficient of one type of commercial conductor was tested and compared to examine the accuracy of the model conductor’s simulation to the commercial one. The results show that the simulation by model conductor has high accuracy. The drag coefficients of the lee-ward conductors as well as the global drag coefficients of the 2-boundled conductors grow with the increase of bundle spacing， but they are all much smaller than the value recommended in the current design standards. The global drag coefficients of the 2-boundled conductors decrease at first， and then rise with the increase of wind velocity; however， they are all much smaller than that of a single conductor in all wind velocity. The recommended value of the global drag coefficient of the multi-bundled conductors in the current design standard is on the high side and can be reduced by taking the shielding effect into consideration.