Application of Wavelet-Filtering Techniques to Intermittent Turbulent and Wall Pressure Events. Part 2. Detection of Cluster Patterns.
Abstract
Large amplitude wall-pressure events, observed beneath a turbulent boundary layer, appear to be signatures of intermittent organized motions within the turbulent flow. Experimental studies were made investigating this relationship. Part 1 presented the first phase of this investigation and reported on the results of utilizing time-frequency localization techniques (wavelet transforms) for the detection of these events. The application of wavelet filtering for the analyses of turbulent data was introduced. This report presents the results of the second phase of the investigation. A wavelet filter was selected based on maintaining the integrity of intermittent near wall burst events. The correlations between individual turbulent flow and wall-pressure events were confirmed using both the original time records and the generated VITA function time records. A Localized Windowed Peak Detection algorithm was developed that detects the groupings of these events. The algorithm detects the temporal locations and durations of the clusters. Correlation and conditional sampling methods were then used to postulate the sequential burst events contained within the individual clusters. Conditional sampling showed a bi-directional relationship between positive wall-pressure events and burst ejections in the near-wall region. (AN)
Document Details
- Document Type
- Technical Report
- Publication Date
- Apr 26, 1995
- Accession Number
- ADA293805
Entities
People
- Mario J. Casarella
- Mark E. Kammeyer
- Pablo B. Penafiel
Organizations
- The Catholic University of America