Simulation for the Effects of Aerodynamic Actuation on the Reentry Vehicle Plasma Sheath

A plasma sheath will be generated around the hypersonic vehicle during reentry, and a large number of electrons in the plasma sheath will seriously affect the communication of the vehicle. In order to reduce the electron density of plasma sheath, based on the air dissociation and ionization model including seven components and 18 chemical reactions, the reduction effect of aerodynamic actuation on the electron density of plasma sheath is studied by numerical simulation. First, the plasma flow field around RAMC-II vehicle at an altitude of 30 km is calculated. The calculated electron density distribution is basically consistent with flight test and NASA data. On this basis, the effects of aerodynamic actuation with different number and pressure on the electron density of the plasma sheath is studied. The simulation results show that aerodynamic actuation hinders the incoming flow from flowing downstream, reduces the velocity and temperature of the downstream flow field, ultimately resulting in a significant attenuation of the downstream electron density. The attenuation of the electron density caused by double aerodynamic actuation is significantly greater than that caused by single actuation, with a maximum attenuation amplitude of about 75%. Finally, the propagation characteristic of electromagnetic (EM) wave of 5.8 GHz (
$C$
-band) frequency in the plasma sheath is studied by simulation. The results indicate that after the sheath is disturbed by aerodynamic actuation, the signal loss of electromagnetic wave is significantly reduced, with a maximum reduction of about 20 dB.