Effect of the inter-car gap length on the aerodynamic characteristics of a high-speed train

Abstract

In wind tunnel experiments, the inter-car gaps are designed in such a way as to separate the force measurements for each car and prevent the interference between cars during tests. Moreover, the inter-car gap has a significant effect on the aerodynamic drag of a train. In order to guide the design of the inter-car gaps between cars in wind tunnel experiments, the impact of the inter-car gap length on the aerodynamic characteristics of a 1/8th scale high-speed train is investigated using computational fluid dynamics. The shear stress transport k-! model is used to simulate the flow around a highspeed train. The aerodynamic characteristics of the train with 10 different inter-car gap lengths are numerically simulated and compared. The 10 different inter-car gap lengths are 5, 8, 10, 15, 20, 30, 40, 50, 60, and 80 mm. Results indicate that the aerodynamic drag coefficients obtained using computational fluid dynamics fit the experimental data well. Rapid pressure variations appear in the upper and lower parts of the inter-car gaps. With the increase of the inter-car gap length, the drag force coefficient of the head car gradually increases. The total drag force coefficients of the trains with the inter-car gap length less than 10 mm are practically equal to those of the trains without inter-car gaps. Therefore, it can be concluded from the present study that 10 mm is recommended as the inter-car gap length for the 1/8th scale highspeed train models in wind tunnel experiments.

Effect of RANS Turbulence Model on Aerodynamic Behavior of Trains in Crosswind

“…For RANS, the standard k-ε and Realizable k-ε turbulence model were used to predict the aerodynamics of the vehicles [13,14]. It has been verified that the SST k-ω turbulence model can better predict the aerodynamic forces and pressure on the train surface [15][16][17]. Large eddy simulation (LES) and detached eddy simulation (DES) method were also used to study the aerodynamic performances of trains [18][19][20][21][22].…”

Effect of Braking Plates on the Aerodynamic Behaviors of a High-Speed Train Subjected to Crosswinds

“…The model consists of head and middle car. Li et al [26] used this model (head car, middle car, and tail car) as the object to research the influence of inter-car clearance extent on the aerodynamic performance of the train. In this paper, our focus is on the head car of the train.…”

“…Therefore, we finally determined that the train speed is 250 km/h, and the wind speed is 15 m/s. The aerodynamics of trains has always been a research hotspot, and many simulation studies on it have been published [14,[26][27][28]. Therefore, it can provide references for the selection of related turbulence models and other parameters in this paper.…”

An improved delayed detached eddy simulation study of the bogie cavity length effects on the aerodynamic performance of a high-speed train

“…8–10 Most of the research in this field focuses on the improvement of the shape of the streamlined parts of trains, 10–12 on the optimization pantographs shapes, 13 or inter-carriage gap structures. 14…”