Multi-resolution analysis of the large-scale coherent structure in a turbulent separation bubble affected by an unsteady wake

Unsteady separated and reattaching turbulent flow over a two-dimensional square rib

“…MODWT is characterized as a zero-phase filter, showing its potential for analyzing instantaneous scale-variant signals, which is of considerable practical significance in detecting intermittent vortical events using arrayed sensors. Details regarding the fundamentals and procedures of the transformation can be found in Percival and Walden (2000) and Chun et al (2006), respectively. Multi-resolution instantaneous signals of the wall pressure at x/H ¼ 9.75 are plotted in Fig.…”

“…11. By using MRA, the original time-series signals are extracted to a series of band-passed details, D n , D nÀ1 ,y,D 2 ,D 1 , at successively smaller central frequency levels, as well as the low-passed smooth part S n (Chun et al, 2006). The central frequency related to each scale of the detailed part is successively halved with increasing the level, as can be seen in the autospectrum of the corresponding multi-resolution wall pressure shown in Fig.…”

Analysis of Geophysical Time Series Using Discrete Wavelet Transforms: An Overview

“…Other examples of the use of MRAs in geophysics include the analysis of subtidal sea level fluctuations [23], magnetic storm activity [24], the Lisbon and Gibraltar North Atlantic Oscillation winter indices [25], spatial variation of microflora abundance in agricultural soil [26], the December 26th 2004 tsunami as recorded along the southeastern coast of Brazil [27] and largescale coherent structures in turbulent separation bubbles [28].…”