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

초록

The advantages of LES have been recognized as suitable for analyzing the flow field in which massive vortices occur such as fire-driven flow, and the phenomenon of unsteady flow is predominant. However, one drawback of LES is that compared with RANS, it requires a longer calculation time. Another serious drawback is that its flow prediction capability in the near wall region is markedly less than RANS. To overcome this weakness, methods of significantly increasing the number of grids in the near wall region are being used, but it increases the calculation time exponentially, drawing unfavorable comments on the desirability of its practical applications. Therefore, when employing FDS code that uses the LES technique, it is necessary that such LES advantages be utilized, while avoiding its disadvantages.