Novel analysis method: Multiscale Proper Orthogonal Decomposition mPOD

Filter Banks and POD for feature detection with multiple important frequencies

In collaboration with our partners Prof. Miguel Mendez and Prof. Jean-Marie Buchlin from the von Karman Institute for Fluid Dynamics (VKI), we published work on a combination of multiresolution analysis and a standard Proper Orthogonal Decomposition in the journal Measurement Science and Technology.

Mean free-stream velocity over time
Mean free-stream velocity over time

The studied test case is a cylinder flow with a Reynolds number of about Re ~ 4000. During the time-resolved experiment, the flow moves from a steady-state condition at about 12m/s to a second steady state at about 8m/s passing through a fast transition.

Spectra of the steady states
Spectra of the steady states

The goal of the mPOD is to achieve a compromise between decomposition convergence and spectral purity of the resulting modes. The mPOD reveals the frequency jitter phenomenon in the stationary cylinder wake and correctly identifies the transition from various stationary regimes in the transient test case.

mPOD filter bands and spectra
mPOD filter bands and spectra

Want to know more?

PIV: Our PIV pages

Paper: mPOD in MST

Collaboration Partner: VKI homepage