Influence of perforated wind-break wall on the aerodynamic characteristics of positive feeder in gale areas

Abstract:

The Lanzhou-Urumqi high-speed railway has suffered from wind disasters all year round. The construction of wind-break wall not only ensures the safety of train operation, but also intensifies the galloping of catenary positive feeder. In view of the deficiency of existing wind-break wall in gale areas that “only prevents trains but not catenary”. In this paper, a kind of perforated wind-break wall was designed, and a computational domain model was established based on the theory of fluid mechanics. The wind protection effect of the wind-break wall was evaluated, and the response laws of the porosity and opening angle of the wind-break wall to the aerodynamic characteristics of the positive feeder was analyzed by simulation. The results show that after the wind-break wall was set with a certain porosity, it will impact the vortex flow field behind the wind-break wall, making the flow field tend to be stable. With the increase of the porosity of wind-break wall, the range of the airflow growth zone at the positive feeder of the catenary decreases significantly, and the aerodynamic coefficient of the positive feeder shows a significant downward trend. When the porosity of the wind-break wall was 0.3, the residual coefficient of wind velocity at the leeward side of the wind-break wall was 0.46-0.69. At the same time, the drop rate of lift and drag coefficient of the positive feeder were more than 41.56% and 24.59%,respectively. When the porosity of the wind-break wall was 0.3 and the opening angle was 150°, the aerodynamic coefficient on the positive feeder decreases significantly compared with other angles, which can play a certain role in restraining the galloping of the positive feeder. The research results can provide a certain theoretical reference for the galloping prevention of the catenary positive feeder in gale areas of the Lanzhou-Urumqi high-speed railway.