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Based on the numerical method for solving Navier-Stokes equations and the Wentzel-Kramers-Brillouin(WKB) method for solving wave equations, the computational codes for simulating the reentry plasma flow and its effects on the electromagnetic wave transmission are developed. The methods are validated preliminarily by comparing the computational results with the experimental ones for flight conditions. On the basis of the numerical simulation of the plasma flow field，the transmission characteristics of the electromagnetic wave in plasma flow are computed, and the effects of the surface catalysis and the plasma collision frequencies on the electromagnetic wave transmission are analyzed. The research shows that the effects of the surface catalysis are more important with reentry height increasing, and the collision frequencies can influence severely the transmission of the electromagnetic wave when its frequencies are lower than the characteristic collision frequencies of plasma. [ABSTRACT FROM AUTHOR]

The scattering characteristics of a hypersonic near space vehicle are studied in this paper. The research takes into account the effect of the surrounding flow and wake on the radar cross section (RCS) of the near space hypersonic vehicle. The results show that the maximal plasma density of the surrounding flow, near wake and part of the far wake is higher than the critical plasma density of the ionosphere and much higher than the critical plasma density of the over-the-horizon radar whose frequency ranges from 3 MHz to 30 MHz. The plasma wake may be seen as conducting observation when the radar frequency is lower than the plasma frequency. So the RCS of the plasma wake is even larger than the hypersonic vehicle. On the basis of the numerical analysis，we suggest to detect the near space hypersonic vehicle by an over-the-horizon radar, which may provide longer reaction time for a radar warning system. [ABSTRACT FROM AUTHOR]

Considering high temperature air chemical reactions, gas molecules vibrational excitation, non-equilibrium effects in the flow and the catalytic effect on the vehicle surface, the numerical simulation method and the corresponding computational codes are developed for the aero-thennal environment of the thermo-chemical non-equilibrium flow by solving 3-D thermochemical non-equilibrium Navier-Stokes equations and the mass and energy balance on the surface of the vehicle. The numerical results of the typical example are inconsistent well with the foreign reference data. On this basis, the influence of the local catalytic property distinction is studied for the aero-thermal environment of a hypersonic vehicle with the heal flux sensor under different conditions. These results show that the local catalytic property distinction could obviously lead to the jump heat flux. In some cases, when the local catalytic property distinction is larger, the heat (lux is far higher than the result under the full catalytic surface condition of the whole vehicle surface. In ihe conditions of this paper, it is found that the lower the flight altitude and the greater the Mach number is, the more obvious ihe influence caused by the catalytic property dislinclion is. The influence degree is also relevant to the flight attack angle and the surface temperature. Under the similar conditions,the influence degree is more obvious when the surface temperature is higher. [ABSTRACT FROM AUTHOR]