An experimental study has been conducted to investigate unsteady flow phenomena observed within various two-dimensional configurations of shock/boundary layer interactions.
Six configurations have been tested in Mach 2 flow: ϕ1 = 14◦ and 20◦
compression ramps,
and incident shock reflections from ϕ1 = 7◦
, 8
◦
, 9
◦
, and 10◦
shock generators; Reynolds
numbers in each case are Reθ ≈ 8350. The flow is assessed using an array of fast-response
pressure transducers in conjunction with a high-repetition rate PIV system. Development
of the mean flow structures early in each interaction is observed to be consistent with
the Free Interaction concept. Unsteady wall-pressure energy content at frequencies above
those associated with the characteristic low-frequency shock motion also show significant
similarities in the vicinity of the shock foot. Results confirm that this low-frequency peak
is not associated with a narrow-band forcing mechanism from either upstream or downstream, but rather a characteristic frequency that varies with interaction strength, which
describes the flow’s dynamic response. These findings support various models published in
literature that have sought to explain the source of low-frequency unsteady shock motion.