1. Key Laboratory of Traffic Safety on the Track of Ministry of Education, School of Traffic and Transportation Engineering, Central South University, Changsha 410075, China
2. Joint International Research Laboratory of Key Technology for Rail Traffic Safety, Central South University, Changsha 410075, China
3. National & Local Joint Engineering Research Center of Safety Technology for Rail Vehicle, Changsha 410075, China
4. Division of Fluid Dynamics, Department of Mechanics and Maritime Sciences, Chalmers University of Technology, SE-41296 Gothenburg, Sweden
5. Aerodynamics, Volvo Cars, SE-41878 Gothenburg, Sweden