  The present numerical investigation focuses on the leading edge bluntness
effects on the double-wedge with varied aft-wedge angles exposed to low
enthalpy hypersonic free stream conditions. The bluntness ratio in this study
varies, ranging from R/L1 = 0 (sharp leading edge) to R/L1 = 0.577 (maximum
allowable bluntness), along with the aft-wedge angle varying between {\theta}2
= 450 and 600. Noticeably, even a small bluntness ratio can completely change
the shock interaction pattern compared to its sharp geometrical counterpart due
to a detached leading edge shock, enlarged separation bubble, and location of
various shock-waves concerning it. Critical bluntness ratios exist for the low
aft-wedge {\theta}2 = 450 angle, but increasing the aft-wedge angle makes the
flow field highly unsteady for some bluntness ratios. Nevertheless, these
bluntness ratios for such double-wedge configurations are reported using the
mean of separation bubble size. Moreover, this work unravels the cause of such
unsteadiness for the unsteady flow-fields using the spatial-temporal evolution
of the wall pressure distribution, Fast Fourier Transform (FFT) of the pressure
fluctuation signal at the compression corner and supports the deduced
observation with the help of energy-based Proper Orthogonal Decomposition
(POD). The increased shock-boundary layer interaction strength moves the
separation point upstream beyond the junction of cylindrical bluntness and
inclined fore-wedge surface, accompanying sudden change in its direction of
motion that perturb the shear layer that set to a self-sustained, highly
unsteady flow field.
