Effect of the Cavity Edge Topology on the Aerodynamic Noise of a Pantograph in High-Speed Train

• • The convex-edged cavity (Case 3) reduces the total sound power level (SWL) by 3.3 dB and 2.7 dB(A) relative to the base cavity, with SPL reductions of 2.3 dB(A) at the top receiver and 1.8 dB(A) at the side receiver. This translates to a 50% reduction in acoustic energy, directly mitigating community noise annoyance near high-speed rail corridors. • • Aerodynamic force coefficients are substantially improved: RMS drag coefficient drops from 0.026 to 0.023 (11.5% reduction), RMS lift coefficient from −0.06 to −0.038 (36.7% reduction), mean drag coefficient from 0.23 to 0.18 (21.7% reduction), and mean lift coefficient from −1.3 to −0.85 (34.6% reduction). These reductions lower structural fatigue loads on pantograph components, extending maintenance intervals and operational reliability. • • At a train speed of 300 km/h, the convex cavity lowers noise at the top receiver from 81.9 dB to 77.3 dB (4.6 dB reduction) and at the side receiver from 68.4 dB to 63.1 dB (5.3 dB reduction) in the scaled model. This corresponds to a 65–70% reduction in sound pressure, addressing the dominant aerodynamic noise source that becomes critical above 250 km/h. • • The cavity contribution to overall noise is reduced by 4.2 dB at the top receiver and 5.4 dB at the side receiver, demonstrating that edge topology modification effectively disrupts vortex shedding and flow separation. This passive control strategy requires no moving parts or power input, offering a cost-effective retrofit for existing pantograph systems.