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http://dx.doi.org/10.12989/was.2015.20.5.661

Rectangular prism pressure coherence by modified Morlet continuous wavelet transform  

Le, Thai-Hoa (Department of Civil and Environmental Engineering, Northeastern University)
Caracoglia, Luca (Department of Civil and Environmental Engineering, Northeastern University)
Publication Information
Wind and Structures / v.20, no.5, 2015 , pp. 661-682 More about this Journal
Abstract
This study investigates the use of time-frequency coherence analysis for detecting and evaluating coherent "structures" of surface pressures and wind turbulence components, simultaneously on the time-frequency plane. The continuous wavelet transform-based coherence is employed in this time-frequency examination since it enables multi-resolution analysis of non-stationary signals. The wavelet coherence quantity is used to identify highly coherent "events" and the "coherent structure" of both wind turbulence components and surface pressures on rectangular prisms, which are measured experimentally. The study also examines, by proposing a "modified" complex Morlet wavelet function, the influence of the time-frequency resolution and wavelet parameters (i.e., central frequency and bandwidth) on the wavelet coherence of the surface pressures. It is found that the time-frequency resolution may significantly affect the accuracy of the time-frequency coherence; the selection of the central frequency in the modified complex Morlet wavelet is the key parameter for the time-frequency resolution analysis. Furthermore, the concepts of time-averaged wavelet coherence and wavelet coherence ridge are used to better investigate the time-frequency coherence, the coherently dominant events and the time-varying coherence distribution. Experimental data derived from physical measurements of turbulent flow and surface pressures on rectangular prisms with slenderness ratios B/D=1:1 and B/D=5:1, are analyzed.
Keywords
bluff body; time-frequency analysis; turbulence; pressure distribution; flow separation/attachment/reattachment;
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1 Bendat, J.S. and Piersol, A.G. (2000), Random data: analysis and measurement procedures, 3rd Ed., John Wiley and Sons.
2 Bruno, L., Salvetti, M.V. and Ricciardelli, F. (2014), "Benchmark on the aerodynamics of a rectangular 5:1 cylinder: An overview after the first four years of activity", J. Wind Eng. Ind. Aerod., 126, 87-106.   DOI
3 Bruns, A. (2004), "Fourier-, Hilbert- and wavelet-based signal analysis: are they really different approaches?", Neutroscience Methods, 137, 321-332.
4 Daubechies, I. (1992), Ten lectures on wavelets, Society of Industrial and Applied Mathematics, Philadelphia.
5 Davenport, A.G. (1963), "The response of slender, line-like structures to a gusty wind", Proceedings of Institution of Civil Engineers, 23, 389-408.
6 Geurts, C.P.W., Hajj, M.R. and Tieleman, H.W. (1998), "Continuous wavelet transform of wind and wind-induced pressures on a building in suburban terrain", Wind Eng. Ind. Aerod., 74-76, 609-617.   DOI
7 Grinsted, A., Moore, C. and Jevrejeva, S. (2004), "Application of the cross wavelet transform and wavelet coherence to geophysical time series", Nonlinear Proc. Geoph., 11, 561-566   DOI
8 Gurley, K., Kijewski, T. and Kareem, A. (2003), "First- and high-order correlation detection using wavelet transform", J. Eng. Mech. - ASCE, 129(2), 188-201.   DOI
9 Jakobsen, J.B. (1997), "Span-wise structure of lift and overturning moment on a motionless bridge girder", J. Wind Eng. Ind. Aerod., 69-71, 795-805.   DOI   ScienceOn
10 Kareem, A. and Kijewski, T. (2002), "Time-frequency analysis of wind effects on structures", Wind Eng. Ind. Aerod., 90, 1435-1452.   DOI
11 Kijewski, T. and Kareem, A. (2002), "On the presence of end effects and their melioration in wavelet-based analysis", J. Sound Vib., 256 (5), 980-988.   DOI
12 Kijewski, T. and Kareem, A. (2003), "Wavelet transform for system identification in civil engineering", Comput. - Aided Civil. Infrastruct. Eng., 18, 339-355.   DOI
13 Krenk, S. (1996), "Wind field coherence and dynamic wind forces", IUTAM Symposium on "Advances in nonlinear stochastic mechanics", (Eds. Naess, A. and Krenk, S.), Kluver Academic Publishers, Netherlands.
14 Ladies, J. and Gouttebroze, S. (2002), "Identification of modal parameters using wavelet transform", Int'l J. Mechanical Sci., 44, 2263-2283.   DOI
15 Liu, P.C. (1994), "Wavelet spectrum analysis and ocean wind waves", Wavelets in Geophysics, (Eds. Foufoula-Georgiou, E. and Kumar, P.), Academic Press.
16 Larose, G.L. (1996), "The span-wise coherence of wind forces on streamlined bridge decks", Proceedings of the 3rdInternational Colloquium on Bluff Body Aerodynamics and Applications (BBAA3), Blacksburg, USA.
17 Le, T.H., Matsumoto, M. and Hiromichi, H. (2009), "Spanwise coherent structure of wind turbulence and induced pressure on rectangular cylinders", Wind Struct., 12(5), 441-455.   DOI   ScienceOn
18 Le, T.H., Tamura, Y. and Matsumoto, M. (2011), "Spanwise pressure coherence on prisms using wavelet transform and spectral proper orthogonal decomposition based tools", Wind Eng. Ind. Aerod., 99, 499-508.   DOI   ScienceOn
19 Matsumoto, M., Shirato, H., Araki, K., Haramura, T. and Hashimoto, T. (2003), "Spanwise coherence characteristics of surface pressure field on 2-D bluff bodies", J. Wind Eng. Ind. Aerod., 91, 155-163.   DOI
20 Staszewski, W.J. (1998), "Identification of non-linear systems using multi-scale ridges and skeletons of the wavelet transform", J. Sound Vib., 214(4), 639-658.   DOI
21 Simonovski, I and Boltezar, M. (2003), "The norms and variances of the Gabor, Morlet and general harmonic wavelet functions", J. Sound Vib., 264(3), 545-557.   DOI
22 Torrence, C. and Compo, G.P. (1998), "A practical guide to wavelet analysis", B. Am. Meteorol. Soc., 79(1), 61-78.   DOI
23 Yan, B.F., Miyamoto, A. and Bruhwiler, E. (2006), "Wavelet transform-based modal parameter identification considering uncertainty", J. Sound Vib., 291, 285-301.   DOI
24 Zhan, Y., Halliday, D., Jiang, P., Liu, X. and Feng, J. (2006), "Detecting time-dependent coherence between non-stationary electrophysiological signals - A combined statistical and time-frequency approach", Neuroscience Methods, 156, 322-332.   DOI