Aerodynamic influence of the clearance under the cowcatcher of a high-speed train. Issue 220 (January 2022)

• Record Type: Journal Article
• Authors: Guo, Zijian; Liu, Tanghong; Xia, Yutao; Liu, Zhen
• Is Part Of: Journal of wind engineering and industrial aerodynamics. Issue 220(2021)
• Publication Date: 2022-01
• Subjects: High-speed train -- Aerodynamics -- Cowcatcher -- Ground clearance -- Underbody flow; Wind-pressure -- Periodicals; Buildings -- Aerodynamics -- Periodicals; Pression du vent -- Périodiques; Constructions -- Aérodynamique -- Périodiques; Buildings -- Aerodynamics; Wind-pressure; Periodicals
• DOI: 10.1016/j.jweia.2021.104844
• Languages: English
• ISSNs: 0167-6105

Abstract

Abstract: The improved delayed detached-eddy simulation (IDDES) method is used to investigate the aerodynamic performance of a high-speed train with cowcatchers having different ground clearances. The numerical results were verified by wind tunnel tests, and validation on the Reynolds number and geometry generality were also conducted. It was proved that the ground clearance under the cowcatcher has a significant effect on the train's time-averaged and transient aerodynamic forces. A smaller ground clearance reduces the aerodynamic drag of the front part of the train body, strength the negative lift while increases the drag of the middle and rear parts as well as the positive lift. Smaller ground clearance also significantly reduces the aerodynamic of its neighboring downstream components. A lower ground clearance makes its power spectral (PS) value stronger and increases the dominant frequency of the neighboring downstream components. The flow pattern on the train body and its surroundings will also be locally affected by the ground clearance, such as slipstream and vorticity distribution. Highlights: Ground clearance of cowcatcher is a significant factor to train aerodynamics. Smaller ground clearance reduces the aerodynamic drag of head car while increase others. Flow patterns are locally affected by the ground clearance. The conclusions about aerodynamic drag are generical to other high-speed trains.