Detached eddy simulation of flow characteristics around railway embankments and the layout of anemometers
Journal article, 2019

Anemometers are usually set up along railway embankments to monitor wind speeds, and the layout for them has to be investigated. This work used an improved delayed detached eddy simulation (IDDES) approach to explore the flow properties around railway embankments, and then a proposal was put forward for the layout of anemometers. The numerical method was validated against previous wind tunnel tests on the speed-up ratios of the flow around a 1/300 scale two-dimensional embankment with the slope gradient of 1:2. The effects of inlet velocity profiles, i.e., uniform velocity and atmospheric boundary layer velocity profiles, on the speed-up ratios around a 5 m high railway embankment were compared. The study indicates that using a uniform velocity profile to assess the operational safety of trains running across strong wind regions could be favourable, especially when complex local terrains contribute to different wind characteristics. The anemometers should be set upstream, i.e., at a well defined distance in locations with sufficient extent of open ground and on the electrification masts along railway lines. This is not in line with the anemometer layout of the existing SWEWS (Strong Wind Early Warning Systems), the difference being due to the speed-up effect of the railway embankment, which is usually not considered explicitly. Formulas have been developed on the basis of regression of the simulation results to express the relationships between e.g. top wind speed over the embankment (located in an area where it is not possible to install anemometers) and measured wind speeds. In this way it is possible to take into account the speed-up effect encountered by the wind passing over the embankment, which needs to be considered in the operational rules in order to ensure safe operations.

Railway embankment

Flow structure

Speed-up factor

Atmospheric boundary layer

Uniform wind profile

IDDES

Author

Jie Zhang

Central South University

Chalmers, Mechanics and Maritime Sciences, Fluid Dynamics

Jiabin Wang

National & Local Joint Engineering Research Center of Safety Technology for Rail Vehicle

Central South University

Xiaoming Tan

National & Local Joint Engineering Research Center of Safety Technology for Rail Vehicle

Central South University

Guangjun Gao

National & Local Joint Engineering Research Center of Safety Technology for Rail Vehicle

Central South University

Xiaohui Xiong

National & Local Joint Engineering Research Center of Safety Technology for Rail Vehicle

Central South University

Journal of Wind Engineering and Industrial Aerodynamics

0167-6105 (ISSN)

Vol. 193 103968

Subject Categories

Meteorology and Atmospheric Sciences

Vehicle Engineering

Fluid Mechanics and Acoustics

DOI

10.1016/j.jweia.2019.103968

More information

Latest update

11/8/2019