Effect of characteristic parameters of air-bleeding/blowing interface on tunnel pressure waves in streamlined regions of high-speed trains: A numerical simulation study

•An active flow control technology to mitigate aerodynamic effects in tunnels.•Bleeding/blowing interfaces are respectively arranged at the head/tail of trains.•Effect of the characteristic parameters of interfaces on tunnel pressure waves.•Effect of bleeding/blowing interfaces on the flow field around the train. In this study, interface attribute control technology was adopted to set bleeding/blowing interfaces in the streamlined regions of a train head and tail to alleviate tunnel pressure waves (TPWs). The effects of the position of the attribute-controllable interface and the flow speed on the TPWs were investigated. The results show that the overall amplitude effect of pressure waves (PWs) is independent of the bleeding/blowing interface location. The ΔP reductions were similar (less than 5%), with some differences only at the tail of the train. Low bleeding/blowing speeds (< 5 m/s) did not affect the PW distribution along the train/tunnel, while ΔP significantly reduced (14%). When the bleeding/blowing speed reached 20 m/s, the Pmin value at the train body decreased by 33%–56%, and the Pmax value at the tunnel entrance decreased by approximately 28%. However, high bleeding/blowing speeds did not reduce Pmax in the central region of the train/tunnel. Further, at the bleeding/blowing speed of 10 m/s, the overall PW amplitude reduced the most, with ΔP of 20% for the train body and in the range of 7%–20% for the tunnel wall.