Differential interferometric measurement of instability in a hypervelocity boundary layer

N. J. Parziale, J. E. Shepherd, H. G. Hornung

Research output: Contribution to journalArticlepeer-review

131 Scopus citations

Abstract

A quantitative nonintrusive optical scheme, focused laser differential interferometry (FLDI), used to investigate disturbances in a hypervelocity boundary layer on a 5 deg half-angle cone, is described. All experiments were performed in T5, the reflected shock tunnel at the California Institute of Technology. The test article was a 1 m long 5 deg half-angle aluminum cone, and the test gas was air. A relation between the fluctuations in density and output voltage from the photodetector is used for postprocessing. The spectral content of the turbulent spot shows broadband response; the wave packet has a strong peak in response at 1.11 MHz. The largest sources of systematic error are considered to be the uncertainty introduced by the assumed integration length, assumed to be 20%. Random error from electrical noise and mechanical vibrations can be estimated by inspecting the spectral content of the signal immediately preceding the test time.

Original languageEnglish
Pages (from-to)750-753
Number of pages4
JournalAIAA journal
Volume51
Issue number3
DOIs
StatePublished - Mar 2013

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