Browsing by Author "Abel, Demissie"

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    Stability of trains under aerodynamic excitation for Addis Ababa Light railway transit (A.A.L.R.T)
    (AAU, 2015-05) Abel, Demissie; Habtamu, Tkubet
    Railway train aerodynamic problems are closely associated with the flows occurring around train. This work is based on numerical model using Computational Fluid Dynamics (CFD) approach to obtain the impact of air flow around a train operating in selected scenarios. These scenarios are train passing each other and train passing through the tunnel. The model of generic passenger train was developed using CatiaV5 and generated the wind tunnel and applied the boundary conditions in ANSYS workbench 13.0. The simulation work of the test vehicle and grid system is constructed by ANSYS-13.0. FLUENT which is the CFD solver and employed in the present work. In this study, numerical iterations are completed, then after aerodynamic data and detailed complicated flow structure are visualized The paper aimed at investigating the aerodynamic impact on a lightweight railway vehicle used in A.A.LRT. The performed simulation allows measuring the aerodynamic forces on the vehicles. Numerical prediction of incompressible flow has been performed in AALRT train moving at a speed of 22.2m/s (80k/hr). Fluent, the CFD code which incorporates - turbulence model and segregated implicit solver was used for the computation. The aerodynamic analysis was performed to study the flow behavior of the air over the train body. The analysis includes the study of contours of pressure and velocity. The peak pressure difference along the train is 1615KPa which is exhibited for trains passing each other. The two scenarios conducted for a train exiting and entering the tunnel shows that the pressure deviation is very low with a magnitude of 1411Kpa and 1355Kp respectively