Influence of Types of Steel Poles on Measurements by Wind Speed Sensors along High-Speed Railways

Abstract

To find the influence of different types of steel poles on measurements by wind speed sensors along highspeed railways, the three-dimensional Reynolds-averaged Navier-Stokes equations, combined with the k-e turbulence model, were solved on an unstructured grid with a boundary layer using the finite volume method. The grid-independent validation was firstly conducted, and the accuracy of the present numerical simulation method was validated by experiments and simulations carried out by previous researchers. To ascertain angles of influence at different distances between the sensor and the virtual one, the flow field around a sensor was investigated with the method of altering the relative coordinates between the two sensors. After that, the flow fields and velocity distributions around steel poles were studied. It can be stated that behind the sensor, the closer the distance from the sensor center line, the larger the angle of influence. However, as the distance is varied from 0.3 to 1.0 m, the most adverse angles are not in excess of ±20°. In addition, the steel poles have a certain influence on the measurement results of sensors. A “two-sided petal acceleration region” with a “central pistil deceleration zone” comes into being. From the perspective of regions of influence in different wind directions, the influence region of the annulus pole is basically the same. For the square and H types, when the angle is 45°, the region of effect is the largest. For the same distance between the sensor and the pole, the space required between two sensors for the single H type is larger than that required by the annulus type. Thus, it is suggested that the distance between sensors and the pole should be 1.0 m with the anemometer located on the upstream side, and the distance between two anemometers should be 0.8 m.