The displacement of the flow by a passing freight train can often result in dangerous conditions for railway equipment and people standing in the vicinity of the train. In this work, Computational Fluid Dynamics (CFD) simulations are performed to study the flow development around a moving freight train comprised of a Class 66 locomotive and four container wagons. The results will give a better insight into the effects that each flow structure can have in the flow within the train's slipstream. Both two- and three-dimensional simulations are carried out around the freight train using three different RANS turbulence models: the Spalart-Allmaras, the SST k-ω and the W&J EARSM. Two cases of 10o and 30o crosswinds are also considered and compared to the no-crosswind case, as side-winds characterize the majority of real-life situations and are known to amplify the slipstream effects. The results are validated against available experimental and numerical data and they are thoroughly presented and discussed. The 30o crosswind case is also computed using a DDES simulation. A meshing strategy which involves the assembly of different mesh blocks with a non-matching interface boundary condition to create the complete domain is used and assessed, as an alternative meshing approach that can simplify and accelerate the set-up of different case-studies. Additionally, the two-dimensional study is used to assess the influence of different parameters on the solution, such as the grid resolution and the moving-ground boundary condition.
| Identifer | oai:union.ndltd.org:UPSALLA1/oai:DiVA.org:kth-331176 |
| Date | January 2023 |
| Creators | Stavrinides, Stylianos |
| Publisher | KTH, Teknisk mekanik |
| Source Sets | DiVA Archive at Upsalla University |
| Language | English |
| Detected Language | English |
| Type | Student thesis, info:eu-repo/semantics/bachelorThesis, text |
| Format | application/pdf |
| Rights | info:eu-repo/semantics/openAccess |
| Relation | TRITA-SCI-GRU ; 2023:216 |
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