CFD Analysis of Impact of Rough Surface on High-Speed Rail

Teng, Khai Sheng (2021) CFD Analysis of Impact of Rough Surface on High-Speed Rail. Final Year Project (Bachelor), Tunku Abdul Rahman University College.

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Abstract

High-speed rail (HSR) consumed most of the energy against viscous drag, pressure drag and other complex aerodynamic problem when travelling at high speed. Therefore, this project will study the impact of rough surface structure and determine the optimal design for the drag reduction of the high-speed train. Next, a series of numerical simulations with complex setup carried out using ANSYS Fluent CFD software. The CRH 380A HSR base model with 50m length simulated by using the SST k-ω model, at facing incoming 300km/hr mainstream flow and obtained a verified and validated reference drag coefficient of 0.1901. The rough surface structure such as round pit and jet inlet structure simulated with identical setup in baseline model simulation. Then the simulated results of the round pit and jet inlet structure were discussed and analysed. As the results have significant fluctuation, the average drag coefficient will be determined where 0.1882 for round pit structure and 0.1877 for jet inlet structure. The modified rounded edge round pit structure is the optimal design as it provides the lowest drag coefficient of 0.1844 or 2.98% of aerodynamic drag reduction. It found that the dimension, parameter as well as spacing of the structure affect the flow structure and drag reduction mechanism significantly. The drag reduction mechanism can be categorized in term of viscous sublayer, vorticity, pressure coefficient, turbulent kinetic energy as well as corner radius.