TY - GEN
T1 - Sensing flow separation on a circular cylinder by MEMS thermal-film sensors
AU - Tu, J. K.
AU - Miau, J. J.
AU - Chou, J. H.
AU - Lee, G. B.
N1 - Publication details (e.g. title, author(s), publication statuses and dates) are captured on an “AS IS” and “AS AVAILABLE” basis at the time of record harvesting from the data source. Suggestions for further amendments or supplementary information can be sent to [email protected].
PY - 2005
Y1 - 2005
N2 - By applying a MEMS thermal film sensors array on a circular cylinder and Wavelet analysis on the signals obtained, the unsteady behaviors of laminar flow separation from the cylinder were investigated in this study. The sensor signals obtained at θ=85° revealed that the unsteady behaviors of flow separation are characterized by two time scales, one of which is associated by the frequency of vortex shedding, and the other is at least one order of magnitude longer due to the excursion of flow separation in a circumferential region about 5°. The Wavelet analysis results enabled one to reduce the percentage of time of which the vortex shedding frequency was detectable at the location measured. It is found that the percentage values are very close to 1 in the region upstream of flow separation, followed by a pronounced transition from θ=85° to 100°, at which the percentage values are decreased to about 0.2. Low-frequency variations were noticed in the signals of the thermal films upstream of flow separation, and a hot-wire probe situated in the free stream. Further, a negative correlation between the vortex shedding frequency and its modulus was realized from the hot-wire signals measured in the free stream, inferring that the lower the vortex shedding frequency, the higher the amplitude of the vortex shedding frequency component. Copyright © 2005 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved.
AB - By applying a MEMS thermal film sensors array on a circular cylinder and Wavelet analysis on the signals obtained, the unsteady behaviors of laminar flow separation from the cylinder were investigated in this study. The sensor signals obtained at θ=85° revealed that the unsteady behaviors of flow separation are characterized by two time scales, one of which is associated by the frequency of vortex shedding, and the other is at least one order of magnitude longer due to the excursion of flow separation in a circumferential region about 5°. The Wavelet analysis results enabled one to reduce the percentage of time of which the vortex shedding frequency was detectable at the location measured. It is found that the percentage values are very close to 1 in the region upstream of flow separation, followed by a pronounced transition from θ=85° to 100°, at which the percentage values are decreased to about 0.2. Low-frequency variations were noticed in the signals of the thermal films upstream of flow separation, and a hot-wire probe situated in the free stream. Further, a negative correlation between the vortex shedding frequency and its modulus was realized from the hot-wire signals measured in the free stream, inferring that the lower the vortex shedding frequency, the higher the amplitude of the vortex shedding frequency component. Copyright © 2005 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved.
UR - https://www.scopus.com/pages/publications/30744455050
UR - https://www.scopus.com/record/pubmetrics.uri?eid=2-s2.0-30744455050&origin=recordpage
U2 - 10.2514/6.2005-299
DO - 10.2514/6.2005-299
M3 - RGC 32 - Refereed conference paper (with host publication)
T3 - 43rd AIAA Aerospace Sciences Meeting and Exhibit - Meeting Papers
SP - 12079
EP - 12087
BT - 43rd AIAA Aerospace Sciences Meeting and Exhibit - Meeting Papers
T2 - 43rd AIAA Aerospace Sciences Meeting and Exhibit
Y2 - 10 January 2005 through 13 January 2005
ER -