Demiss, Alemu (PhD)Solomon, Asmamaw2022-05-272023-11-042022-05-272023-11-042016-09http://etd.aau.edu.et/handle/123456789/31807The aerodynamic drag resistance is the main constraint on the performance of high speed rolling stock technology. Its effect increases as speed of train increases and with poor aerodynamic body shape design of high speed train body. Problems such as passenger discomfort, safety conditions reduction, environment disturbance, and more traction power consumptions are main effects of aerodynamic drag resistance. This thesis investigates the effect of aerodynamic drag resistance of passenger rolling stock of two high speed train models with leading car, middle coach, and tail car. The first train model is existing European ICE-2 Regional Train and the second modified train model is called Ehio-HST-250+. The aerodynamic investigation is done using CATIA V5R20 modeling software and ANSYSFluent V 17.0 Computational Fluid Dynamics (CFD) simulation software. The numerical method used on Fluent solver is viscous-incompressible steady state Reynolds Average NavierStock (RANS) and two equation turbulence model of Realizable k - ε model (RKΕ) with Nonequilibrium wall function (NWF) of near wall treatment for the simulation of the system in an open air condition. The input data to the CFD software are collected from relevant literatures with consideration of Ethiopian average air temperature of 25°C for input air property variables. The study does not include passenger discomfort, safety conditions (cross wind, tunnel test etc.), pantograph component, and vibration of the vehicle as time and computing material quality limits. Thus using steady RANS CFD method in open air condition, reduction of coefficient of aerodynamic drag percentage amount of 49.01% of enormous aerodynamic drag is reduced and 636.13 kW traction power is saved. This can increase the safe and comfort environment of the system.en-USANSYS-Fluent V 17.0CATIA V5R20Computational Fluid Dynamics (CFD)Inter City Express (ICE-2 Train)Reynolds Average Navior-Stock (RANS)Realizable k – ε model (RKΕ)Non-equilibrium wall function (NWF)Thesis