Experimental and Numerical Investigation of Coherent Motion in Slugging Gas-Solid Fluidization

Gas-solid flows are characterized by a multitude of coherent flow structures displaying varying spatial-temporal behavior. The novel high speed particle image velocimetry, HSPIV measurement method coupled with advanced signal processing protocols are utilized to identify and characterize these structures. High speed pressure fluctuations from experiments and TFM simulations are also processed to reinforce the findings from the particle velocity fluctuations. Spectral analysis of particle velocity and pressure fluctuations reveal large scale oscillations at low frequencies. The classical Kolmogorov -5/3 power law is obeyed at low frequencies of the particle velocity fluctuations. The time-frequency properties of the bed dynamics are studied using the wavelet coherent analysis and the Hilbert Huang transform. The time localized coherent structures are identified using the wavelet coherence analysis while the multi-resolution of the particle fluctuations is realized with the Hilbert-Huang transform.