Study on the Propagation Laws of Radio Frequency Electromagnetic Fields and Initial Compression Waves when High-Speed Maglev Trains Pass Through Tunnels

Abstract

When the speed of maglev trains reaches 600 km/h, the propagation characteristics of initial compression waves and radio frequency electromagnetic fields formed during their entry into tunnels become increasingly prominent. drawing upon the Navier-Stokes (N-S) equations for compressible viscous fluids and the SST k-ω turbulence model, this paper establishes a three-dimensional aerodynamic model of high-speed maglev trains passing through tunnels. The reliability of the numerical simulation method is verified by comparing with the measured data published in open literature. Meanwhile, a propagation model of radio frequency electromagnetic fields in tunnels has been constructed drawing upon the analysis method of Maxwell's equations and waveguide theory, and the attenuation and reflection characteristics of electromagnetic waves in tunnels are analyzed. The research demonstrates that the initial compression wave exhibits obvious three-dimensional characteristics in the early stage of generation, gradually weakens into a one-dimensional plane wave after propagating 60 m, and the peak value of the pressure gradient continues to increase until it radiates at the tunnel exit to form a micro-pressure wave. The radio frequency electromagnetic field propagates in the tunnel in a waveguide mode, and due to the influence of tunnel geometric constraints and material properties, there are significant signal attenuation and multipath effects. The research results can provide a reference for the aerodynamic effects and communication system optimization of 600 km/h maglev trains passing through tunnels.