S1904-2-4 Visualization of Unsteady Flow around Spiked Body in Supersonic Flow

Flow instability induced by spiked bodies

“…An earlier version, based on the commercially available monochrome high-speed camera HPV-1 built by Shimadzu, had already been applied in another preliminary set of tests which achieved the first MHz-range timeresolved color schlieren visualization of shock wave phenomena [10]. The main difference between the new prototype and the older one described in [5] is the considerably higher resolution (300 000 pixels as opposed to 80 000) and the larger number of frames (144 vs. 100) [3], [4]. Both instruments have in common an In-Situ Storage Image Sensor (ISIS) CCD chip [3], [4], [10] which allows one to achieve frame rates in the MHz range without sacrificing image resolution.…”

“…The combination of the color schlieren visualization and the ultrahigh-speed video camera has proven to be a powerful tool to analyze unsteady flow and first results of a renewed investigation of the aerospike problem have been promising [5]. Although the aerospike has been known since the 1950s' to cause an unstable flow [6], only a limited amount of literature was found that addresses the mechanism how the unstable flow is initiated and how it persists [7][8][9].…”

“…In the previous tests [5] the number of tested configurations was insufficient to clarify the boundaries of the unstable regions. For this reason, two base models that could be equipped with spikes of six different lengths and two different tip shapes were prepared for the tests.…”

Optical imaging techniques for hypersonic impulse facilities

“…A similar high-speed camera, albeit with considerably lower resolution, and its application to hypersonic flow visualisation was described by Wu and Miles (21) . Further development and improvement of these cameras towards higher resolution, increased frame number and colour recording is currently being pursued (22,23) , and the increased use of these devices in hypersonic test facilities is likely to have a significant impact on future research in this field.…”