Experiments in Fluids

, Volume 51, Issue 6, pp 1673–1684 | Cite as

Spectral analysis of phase-shifting measurements of crossflow waves

Research Article
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Abstract

Computing amplitudes of periodic components in a measured signal is commonly encountered in data analysis. When this process is hampered by low-resolution data, it is sometimes possible to exploit certain qualities of the data to mitigate these limitations. In this work, spectral analysis of crossflow vortices measured in flight tests using multi-element hotfilm sensors is accomplished despite restrictive sensor counts. The vortices are nominally steady but subject to randomly changing phase shifts that can be computed to form well-resolved sets of data. The reliability and efficiency of this analysis are tested via Monte Carlo simulation and the uncertainties in detected wavelengths are quantified. This analysis technique is applied to in-flight measurements of crossflow instabilities in swept-wing boundary layers.

Keywords

Discrete Fourier Transform False Alarm Probability Fundamental Wavelength Shear Stress Measurement Input Wavelength 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.
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Notes

Acknowledgments

The authors wish to thank Professor William Saric, Dr. Andrew Carpenter and the faculty, staff and students of the Texas A&M University Flight Research Laboratory for their efforts on the SWIFT program and for providing the data used in the present work. The TAMU SWIFT program was supported by U. S. Air Force Office of Scientific Research through grant FA9550-05-0044 under the direction of Gary Dale, by the U. S. Air Force Research Laboratory under the AEI Program and the Northrop-Grumman Corporation under contract number PO02642706. The authors also wish to thank the staff of Scaled Composites for their efforts on the NGC SensorCraft AEI program and for making these flights tests possible. Special thanks are due to flight test engineers Elliot Seguin and Brandon Wood for collecting the hotfilm data in flight. The AEI program was supported by the U.S. Air Force Research Laboratory under contract number FA8650-05-C-3502, under the direction of Dr. Juan Martinez. Additional support for the present work is due to the the U. S. Air Force Office of Scientific Research under grant FA9550-07-0312 and the Northrop-Grumman Corporation under the direction of Aaron Drake.

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Copyright information

© Springer-Verlag 2011

Authors and Affiliations

  1. 1.Department of Aerospace EngineeringTexas A&M UniversityCollege StationUSA

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