"Demonstration of wavelet techniques
in the spectral analysis of bypass transition data"
Lewalle, J., Ashpis, D.E. and Sohn, H.-K.
We develop and illustrate a number of wavelet-based techniques for the
analysis of experimental data. We used the data of Sohn & Reshotko
(NASA CR 187068, 1991), which consists of
simultaneous hot wire velocity traces in bypass
boundary layer transition on a heated flat plate. Our purpose is
to demonstrate that the results of multiscale analysis apply
to the modeling of related industrial flows.
From the dataset of Sohn & Reshotko, we excerpt a pair of traces
(2 components of velocity) at one location, and we calculate
a number of statistics related to dominant time scales for energy
and for momentum transport, their quadrant distributions,
and their intermittency.
We find that energy-dominant time scales inside spots are poorly
identified, whereas transport-dominant scales inside spots accouidentified, whereas transport-dominant scales inside spots account
for the largest part of the Reynolds stress.
We also observe that momentum transport is much more intermittent
than energetic fluctuations, translating into very rare rare contributions
to transport at between spots.
NASA TP # 3555, 1997.
Jacques Lewalle, email@example.com