배플 플레이트를 가지는 고속철도 터널 출구로부터 방사하는 미기압파에 관한 연구

Study on Impulse Wave Radiated from High Speed Railway Tunnel Exit with Baffle Plate

Abstract

Recently, as the high speed railway becomes more common, new environmental problems such as noise around tunnels are appearing. When a high speed train enters a tunnel, a compression wave in the tunnel is generated and propagated toward the tunnel exit at a sonic speed. When it reaches the tunnel exit, a part of compression wave radiates as a pulse typed impulse wave to the outside of tunnel. The impulse wave has an explosive noise. When the impulse wave is propagated around a village, it induces a serious noise or other problems to the resident. In order to solve these engineering problems, it is important to investigate the radiation characteristics of the impulse wave radiated from the tunnel exit. In this study, the effect of the length and angle of the baffle plate at the tunnel exit on the impulse wave radiated from the tunnel exit was investigated by numerical analysis. As a results, the baffle plate greatly affected the propagation of impulse wave.

Fig. 1. Experimental setups used for validating CFD model

Fig. 2. Comparison of pressure histories between experimental and CFD results inside the low pressure section (Ms =1.1)

Fig. 3. Comparison of pressure histories between experimental and CFD impulse waves at different Ms (r=2D)

Fig. 4. Comparison between experimental and CFD density contours (Ms=1.1)

Fig. 5. Simplified computation domain and boundary conditions

Fig. 6. Pressure histories of impulse wave at locations with different angles at a specific radius of r=2D with different baffle length

Fig. 7. Density contours of impulse waves with the length of baffle plate

Fig. 8. Pressure histories of impulse wave with different baffle angle at different specific radiuses

Fig. 9. Generation and propagation of impulse wave from a tunnel exit with a baffle plate

Table 1. Numerical schemes