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Multiscale Sample Entropy of Two-Dimensional Decaying Turbulence
1Department of Mechanical and Electrical Engineering, Konkuk University, Chungju 27489, Korea.
Entropy (Basel, Switzerland)
|March 6, 2021
Summary
Multiscale sample entropy analysis offers a novel way to study turbulence. This method successfully characterized anisotropic turbulence and decaying flow in soap films.
Area of Science:
- Fluid Dynamics
- Nonlinear Dynamics
- Time Series Analysis
Background:
- Multiscale sample entropy (MSE) quantifies time series complexity and predictability.
- MSE was originally developed for physiological data.
- Conventional methods for turbulence analysis often rely on energetic measurements.
Purpose of the Study:
- To assess the feasibility of applying MSE analysis to turbulence data.
- To qualitatively characterize turbulence without conventional energetic analysis.
- To explore MSE's potential in understanding turbulent flows.
Main Methods:
- Collected time series data of velocity fluctuations (longitudinal and transverse) in turbulent soap film flows.
- Applied multiscale sample entropy analysis to the collected turbulence data.
- Analyzed directional disparities and temporal scales within the data.
Main Results:
- MSE analysis proved promising for characterizing turbulence.
- Successfully identified anisotropy in turbulent soap films through directional disparity.
- Observed an increase in the most unpredictable time scale with downstream distance, indicating turbulence decay.
Conclusions:
- Multiscale sample entropy is a viable tool for qualitative turbulence characterization.
- MSE analysis can reveal key features of turbulent flows, such as anisotropy and decay.
- This approach offers a complementary perspective to traditional energetic analyses of turbulence.
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