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The aim of this study is to investigate experimentally and numerically the effect of the crosswind and wagon numbers to the aerodynamic characteristics as well as fuel consumption of the locomotive Alstom AD43C and some specified passenger wagons behind it. Turbulent, incompressible, and 3D airflow has been considered for numerical simulation. Simulations are carried out for yaw angles 0°, 15°, and 30°for different airflow velocities. A total of 16 pressure tabs were employed to measure the air pressure at various points on the 1:26 scaled model of the train in the experimental investigation. Comparison between the numerical and the experimental results verifies the numerical simulation method. The results show that the variation of the longitudinal force coefficient (LFC) and side force coefficient (SFC) in the middle wagons (except for the first two and last two wagons) is similar. The LFC and SFC of these wagons are 0.239 and 1.251, respectively, for the Reynolds number 1.587 9 10 5 (airflow velocity 30 m/s) and the yaw angle 30°. However, the Reynolds number effect is insignificant. The yaw angle effect on the train fuel consumption is more important. Moreover, the fuel consumption increases by approximately 25 % from the yaw angle 0°to 30°for ten wagons at the Reynolds number 1.587 9 10 5 .

Ferrofluids strongly enhance heat transfer in boiling phenomenon by changing the physical properties of the base fluid. The results will be impressive when the alternating magnetic field with regular frequency is applied to the ferrofluid boiling process. In the present research, pool boiling experiments were conducted using Fe₃O₄/water ferrofluid at three volume concentrations of 0.01%, 0.05%, and 0.1% in two cases. The heater was a nickel-chromium wire with a diameter of 0.1 mm. The alternating magnetic field was generated by a pair of Helmholk coils. The results indicated that the onset of nucleate boiling (ONB) was delayed by increasing the concentration of nanoparticles in the base fluid due to the deposition of nanoparticles and reducing the bubble formation process. Moreover, an increase in CHF (critical heat flux) was observed with an increase in the concentration of nanoparticles from 7% to 46% due to the increase in the deposition on the heater surface. The heat transfer coefficient increased at low concentrations and decreased with increasing concentration. Hence, applying the magnetic field showed that the ONB is accelerated due to more fluid mixing, more homogeneous temperature distribution and, as a result, more heat transfer. Applying Lorenk force by an alternating magnetic field on ferrofluid particles and alternatingly changing its direction resulted in greater fluid circulation and the reduction of bubble retention time around the heater. As a result of more heat transfer and a decrease in the temperature of the wire heater, the heat transfer coefficient showed a significant increase.

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