Impact of the bogies and cavities on the aerodynamic behaviour of a high-speed train. An IDDES study. Issue 207 (December 2020)

• Record Type: Journal Article
• Authors: Wang, Jiabin; Minelli, Guglielmo; Dong, Tianyun; He, Kan; Krajnović, Sinisa
• Is Part Of: Journal of wind engineering and industrial aerodynamics. Issue 207(2020)
• Publication Date: 2020-12
• Subjects: High-speed train -- Improved delayed detached-eddy simulation -- Bogie -- Cavity -- Aerodynamic performance -- Computational cost; Wind-pressure -- Periodicals; Buildings -- Aerodynamics -- Periodicals; Pression du vent -- Périodiques; Constructions -- Aérodynamique -- Périodiques; Buildings -- Aerodynamics; Wind-pressure; Periodicals
• DOI: 10.1016/j.jweia.2020.104406
• Languages: English
• ISSNs: 0167-6105

Abstract

Abstract: This study investigates the effects of bogie cavities and bogies on the aerodynamic behaviour of a high-speed train (HST) using improved delayed detached eddy simulation (IDDES) at R e ​= ​3.3 ​× ​10 5 . The main aim of this work is to identify the individual influence of bogies and cavities on the surrounding flow, thereby revealing aspects to further improve the HST aerodynamic performance. The accuracy of the numerical method has been validated against the experimental data obtained from a previous reduced-scale moving-model test, a wind tunnel test and a full-scale field test. The underbody flow, wake flow, slipstream velocity, aerodynamic drag and the computational costs are compared for three cases. The results show that installing the bogies around the cavities in Case 1 and sealing the cavities in Case 3 can effectively reduce the turbulence kinetic energy ( TKE ) and slipstream velocity around the HST. The cavities in Case 2 produce the highest level of TKE and slipstream velocity distribution in both underbody flow region and the wake region, compared to other two cases. This presents the largest scales of the shear vortices in the cavities and longitudinal vortices in the wake. Compared to Case 2, the TSI values of the slipstream velocity at the trackside position decreases by about 18.9% in Case 1 and 56.9% in Case 3, respectively. The cavities account for approximately 65% of the aerodynamic drag of the HST. Installing bogies in Case 1 and sealing cavities in Case 3 gives a 24% and 56% drag reduction for the overall HST. It is recommended to invest 10% higher resources to achieve an accurate surrounding flow prediction of a HST in presence of bogies. Highlights: IDDES is validated to be a good engineering tool for the prediction of train aerodynamics. The effect of bogies and cavities on train aerodynamics performance is investigated. The underbody flow, wake flow, side flow, drag coefficient are analyzed. The computational cost caused by the selection of different train geometries is compared.