Research on the RCS Scaling Law of Reentry Hypersonic Object With Surrounding Flow and Wake

When a hypersonic object reenters the atmosphere, the formation of an ionized plasma sheath and wake will significantly change its scattering characteristics, causing a significant impact on detection, identification, and tracking. To investigate the relationship between the scattering characteristics of a hypersonic object in ground tests and real flights, in this article, the scaling laws of a hypersonic object with plasma sheath and underdense turbulent wake are derived from the binary scaling law for hypersonic flows, combined with an impedance matching method and the first-order Born approximation method, respectively. We find the radar cross section (RCS) scaling law of a hypersonic object with ionized flow is
$\sigma _{1} /\sigma _{2} =\eta ^{2}\xi $
, while the scaling law for an underdense turbulent wake is
$\sigma _{1} /\sigma _{2} =\eta ^{4}$
when they satisfy the binary scaling law, where
$\sigma _{1} $
and
$\sigma _{2}$
are the RCS of a real flight and ground test,
$\eta $
is a scaling factor, and
$\xi $
is dependent on the dielectric parameters of the plasma sheath. The derived scaling laws can explain the phenomenon of the RCS of the underdense turbulent wake being higher than that of the hypersonic object with plasma sheath under certain conditions and are applied to the RCS simulation of a hypersonic object with ionized flow and underdense turbulent wake.