Research on electromagnetic scattering characteristics of reentry vehicles and blackout forecast model

Vehicles flying at high velocity within the atmosphere become enveloped in a time-varying plasma sheath. This paper adopts a more efficient and stable modified advection upstream splitting method by introducing the pressure-based weight functions (AUSMPW+) to solve the Navier-Stokes equations, calculating aircraft periphery flow field based on Dunn-Kang 11-component air chemical model and obtaining the flow field parameter of different flight speeds. According to the simulation flow field parameter, it applies physical optics method to calculate electromagnetic scattering section of blunt-nosed cone aircraft. Moreover, according to plasma critical frequency of different wave bands, it puts forward a blackout prediction model. The calculation result indicates that when the aircraft has a high-speed flight, with the rising speed of the aircraft, electron density of plasma sheath will increase continuously. Influenced by it, aircraft radar cross section shows a decreasing trend. When electron density inside plasma sheath around aircraft exceeds critical plasma densities of the corresponding communication frequency, it will result in blackout. This model predicts the blackout of S, C, and X wave bands of spacecraft reentry. The result perfectly corresponds to the experimental data. The results obtained in this paper are significant to the guidance technology and communication technique for hypersonic vehicle.