Hypersonic Target Plasma Flow Field Numerical Simulation Of Electromagnetic Characteristics

Pneumatic flow field of the hypersonic aircraft is a complex composition of the ionized gas. As the temperature increases, the degree of ionization of the gas is getting higher and higher. When ionization degree reaches a certain value, the ionized gas renders the collective behavior of the plasma and plasma theory can be used to conduct research and analysis on the gas.Therefore.the aerodynamic flow field around the hypersonic aircraft can be called as plasma-coated flow field, hypersonic plasma or plasma sheath.Firstly,we use the numerical method of FDTD (Finite Difference Time Domain), combined with AUSMPW format,and select the Park’s two-temperature model,the finite rate chemical reaction model to do pneumatic thermal numerical simulation of Typical Aircraft Configuration under the thermochemical nonequilibrium conditions. we get the physical property distribution of the hypersonic flow field.Then.according to the physical property distribution of the field,we get the equivalent dielectric parameters distribution.Because hypersonic aeroheat simulation uses the structured grid, all the plasma dielectric parameters information of the region are stored in the nodes of the hexahedral mesh, electromagnetic numerical simulation uses unstructured tetrahedral mesh.we transfer the information from the the structured grid to the unstructured tetrahedral mesh through coordinate mapping, in order to speed up the efficiency of the information transfer, using the fast multipole grouping ideas which groupes the electromagnetic tetrahedral mesh and flow field hexahedral grid, and then mapped, greatly increasing mapping speed.Finally,we use the FEBI mothod to get the R.CS of the hypersonic target.the analysis of target RCS characteristics in different flight conditions.different flight altitude、different flight speed, is made. At the same time,simulation of the radiation pattern of the antenna covered by an uniform plasma sheath is made.By magnetizing the plasma sheath,the radiation properties of the antenna can be improved.