Yong-Jun Jang

The Comparative Analysis of Slipstream Phenomena by High-Speed and Traditional Train

A series of field tests were performed to develop aerodynamic characteristic evaluation method and countermeasure technology in conventional and high-speed railway. The strength of rolling stock-induced wind which affect the people and substructure in platform and nearby track were investigated. The slipstream of passing trains was measured by hot-wire array system. The speed of trains was 110 - 125km/h for conventional ones and 300km/h for high-speed ones. The streamlined shape trains cause about 50% smaller-scale slipstream compared to the non-streamlined ones.

Effect of Railway Noise Barrier Shape on Solar Radiation Energy Absorption

Abstract The present study aims to determine the optimized shape for the maximum electric energy production of building inte-grated photovoltaic system (BIPV) noise barrier through numerical analysis. The shape of BIPV noise barrier is one of theimportant factors in determining angle difference between direction vector of the sun and normal vector of the sound barriersurface. This study simulated numerically the flow and thermal fields for different angles in the range from 90° to 180°, andfrom the results, the amount of isolation onto noise barrier surface was estimated along the angle between ground and topside of noise barrier. The commercial CFD code (Fluent V. 13.0) was used for calculation. It was found that the maximumamount of insolation per unit area was 19.6 MJ for 105o case during a day in summer and was estimated 12.4 MJ in 150ocase during a day in winter. The results of the summer and winter cases showed the different tendency and this result wouldbe useful in determining the appropriate shape of noise barrier which can be mounted under various circumstances.

The Characteristic Analysis of Fire-Driven Flow Simulation Code (FDS) for Railway Tunnel

The performance and applicability of FDS code is analyzed for flow simulation in rai lway tunnel. RANS and DNS’s results are compared with FDS’s. AJL non-linear k-e model is employed to calculate the turbulent flow for RANS. DNS data by Moser et al. are used to prove the FDS’s applicability in the near wall region. Parallel plate is used for simplified model of railway tunnel. Geometrical variables are non-dimensionalized by the height (H) of parallel plate. The length of streamwise direction is 50H and the length of spanwise direction is 5H. Selected Re numbers are 10,667 for turbulent flow and 133 for laminar low. The characteristics of turbulent boundary layer are introduced. AJL model’s predictions of turbulent boundary layer are well agreed with DNS data. However, the near wall turbulent boundary layer is not well resolved by FDS code. Half-Slip (default) conditions are imposed on the wall but wall functions based on log-law are not employed by FDS. The heavily dense grid distribution in the near wall region is necessary to get correct flow behavior in this region for FDS.