Impact of the train heights on the aerodynamic behaviour of a high-speed train

Abstract

The impact of train heights on train aerodynamic performance is studied by using an improved delayed detached-eddy simulation (IDDES) method. The correctness of the numerical method has been verified by the existing wind tunnel and moving model experiments data. The aerodynamic drag, lift, slipstream, and wake flow are compared for three train heights. The results presented that the drag and lift increased by 6.2% and 23.8% respectively, with an increase in train height from 3.89 m to 4.19 m. Compared with the 3.89 m case, the maximum time-averaged slipstream at the platform location for 4.04 and 4.19 m cases are increased by 2.0% and 4.3% respectively. Meanwhile, the wake topology for three cases is described and analyzed quantitatively. The downwash angle of the wake longitudinal flow is increased with the increasing train height, resulting in the mixing of the downwash flow and the ground flow in advance. The wake in the higher trains tends to develop outward and downward. Besides, the higher trains will also bring greater transient aerodynamic loads to the equipment above the train. It’s recommended to shorten the maintenance period of the electrical equipment above the higher trains to ensure the devices’ safety.

Abbreviations: CFL: Courant–Friedrichs-Lewy; COT: Center of the track; FDR: Flow development region; FFT: Fast Fourier transform; GF: Ground-fixed reference system; ICE3: Intercity Express 3; IDDES: Improved delayed detached-eddy simulation; LES: Large-eddy simulation; LV: Longitudinal vortex; MME: Moving model experiments; NBL: Negative bifurcation line; PBL: Positive bifurcation line; PSD: Power spectral density; RANS: Reynolds averaged Navier – Stokes; SF: Stable focus; SP: Saddle point; STBR: Single-track ballast and rails; SV: Spanwise vortex; TF: Train-fixed reference system; TOR: Top of the track; TSI: Technical specification for interoperability; UN: Unstable node; WPR: Wake propagation region

KEYWORDS:

• Train height
• aerodynamic force
• slipstream
• wake flow
• IDDES

Acknowledgments

The authors acknowledge the computational resources provided by the High-Performance Computing Centre of Central South University, China.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Data availability

The data that supports the findings of this study are available from both the first author and the corresponding author upon reasonable request.

Additional information

Funding

This work was supported by the National Key R&D Program of China (Grant No. 2020YFA0710903); the Natural Science Foundation of Hunan Province (Grant No. 2021JJ30849); the Graduate Student Independent Innovation Project of Hunan Province (Grant No. CX20200196); the Graduate Student Independent Innovation Project of Central South University (Grant Nos. 2020zzts111 and 2020zzts117).