Time-Frequency Analysis and Detection of Supersonic Inlet Buzz

Detection and Transient Dynamics Modeling of Experimental Hypersonic Inlet Unstart

“…Le et al [11] and others [12], [13] for example make use of magnitude, standard deviation and power spectrum techniques that lend themselves to simple thresholding. Trapier et al [14] look at additional frequency techniques such as spectrograms, wavelet transforms, and WignerVille distributions that are specifically designed to highlight time-evolving characteristics of the data. They also present a variety of existing change detection algorithms adapted for identifying abrupt changes in the resulting information.…”

“…A successful algorithm would provide a reasonable detection rate across all four sources with minimal to no human involvement. The most promising algorithm, Cumulative Sum detection (CUSUM), is discussed here and in the reference material [12], [14]. Performance of the algorithm is evaluated on four dissimilar data sets and then compared to the performance of other established change detection algorithms.…”

“…Table 2.1 compares the CUSUM detection times of filtered and unfiltered pressure signals in each of the data sets. In the filtered case, the data is passed through a low-pass filter with at cutoff frequency of 100 Hz (similar in magnitude to the cutoff frequency used in [14]). All algorithm parameters, thresholds, and other data pretreatments are left the same.…”

“…Other work exists in this area and the results of some such work have been considered here in the form of power spectrum based detection [14], [12]. However, none of the precursors have yet shown to provide a consistent, significant feature to use for detection over a wide range of conditions.…”

Effects of Shock Wave/Boundary-Layer Interaction on Performance and Stability of a Mixed-Compression Inlet

“…Much information could be found in the literature on di erent aspects of various types of supersonic inlet models [3][4][5][6][7][8][9][10][11][12][13][14]. Performance characteristics of inlet in cases of extensive maneuvering range [3,4], unstart [5], buzz phenomenon, and application of boundary-layer bleed [6][7][8][9][10][11][12][13][14] have recently been investigated. In addition to these experiments, many computational studies have been accomplished on the supersonic inlet ow and buzz phenomenon as well as ow control methods [15][16][17][18][19].…”