Optimal shape design of medium-speed train based on aerodynamics performance

Train aerodynamic performance greatly affects the efficiency of driving energy and passengers' comfort. This paper aimed to simulate several forms of train models that produce low and stable aerodynamic obstacles as well as low noise at medium speeds of 120-1 50 km/hr. The first step to do was the study of literature on train design models, aeroacoustics, aerodynamics, and human ergonomics. Existing 3D CAD and S-R train models with slender ratios γ = 4, 6, and 8 were tested using Computational Fluid Dynamics (CFD) and Computational Aerospace (CAA) to determine the impact of airflow. The models that have been built were tested at medium speeds of 120 to 150 km/hr. The final simulation results showed that the existing train produced a drag coefficient (Cd) of around 1.27, average noise of 35.9dB, and fuel requirements by 1.7 liters/km. It is different from trains with a slenderness ratio = 6 that produces the best aerodynamic performance with a drag coefficient (Cd) around 0.436, average noise of 9.4 dB, and fuel consumption of 0.73 liters/km. The results concluded that the medium speed needs to adjust the S-R train model with a slenderness ratio γ = 6 that can produce an aerodynamic performance to improve train user comfort and save fuel.