|
|
|
|
| |
|
|
| Elfouhaily, Tanos; Joelson, Maminirina; Guignard, Stéphan; Branger, Hubert; Thompson, Donald; Chapron, Bertrand; Vandemark, Douglas. |
| A generalization of the Woodward's theorem is applied to the case of random signals jointly modulated in amplitude and frequency. This yields the signal spectrum and a rather robust estimate of the bispectrum. Furthermore, higher order statistics that quantify the amount of energy in the signal due to nonlinearities, e.g., wave-wave interaction in the case of water waves, can be inferred. Considering laboratory wind generated water waves, comparisons between the presented generalization and more standard techniques allow to extract the spectral energy due to nonlinear wave-wave interactions. It is shown that our analysis extends the domain of standard spectral estimation techniques from narrow-band to broad-band processes. |
| Tipo: Text |
Palavras-chave: Frequency modulation; Amplitude modulation; Bispectrum; Vertical asymmetry; Horizontal asymmetry; Wave wave interaction; Mode coupling; Fluid mechanics; Modulation de fréquence; Modulation d'amplitude; Bispectre; Dissymétrie horisontale; Dissymétrie verticale; Interaction vague vague; Couplage de mode; Mécaniques des fluides. |
| Ano: 2003 |
URL: https://archimer.ifremer.fr/doc/2003/publication-741.pdf |
| |
|
| |
|
| |
|
|
| Bouhoubeiny, Elkhadim; Druault, Philippe. |
| To enhance the temporal resolution of the PIV measurements of pseudo-periodic turbulent flows, Proper Orthogonal Decomposition (POD) has been previously used to time interpolate PIV database. In this note, it is demonstrated that such POD interpolation is equivalent to the classical mathematical interpolation when dealing with the whole POD eigenfunctions, since POD is a linear transform. In fact, the POD-based time interpolation is only valid for the large scale structures of the flow. The advantage of using POD procedure resides in its efficiency in extracting the dominant flow structures. In this sense, other interpolation methods such as turbulent filtering procedures could provide similar results. To cite this article: E. Bouhoubeiny, P Druault, C R.... |
| Tipo: Text |
Palavras-chave: Fluid mechanics; Particle image velocimetry; Proper orthogonal decomposition; Large scale flow structures. |
| Ano: 2009 |
URL: http://archimer.ifremer.fr/doc/00021/13199/10314.pdf |
| |
|
| |
|
|
|
