Detection of Bursts in a Relaminarizing Turbulent Boundary Layer Using Wavelet Analysis

Abstract

The bursting structure of the turbulent boundary layer under a favorable pressure gradient is experimentally investigated using the continuous wavelet transformation and the variable-interval time averaging technique, abbreviated to VITA technique. By using Gabor function as the analyzing wavelet, ejection and sweep processes as well as the center of burst can be detected independently with high accuracy. The results show that the continuous wavelet transformation with complex mother wavelet function can be one of the most effective technique to investigate bursts in turbulent boundary layer. Furthermore, paying attention to the frequency region which the wavelet coefficient shows the maximum extreme, bursting can be classified approximately by its own time-scale, and bursting structures, such as bursting frequencies, duration of burst are investigated.