PRELIMINARY APPLICATION OF THE HHT TO ANALYZE THE CHARACTERISTICS OF NONLINEAR WAVE DECAY OVER A FLUIDIZED BED

The characteristics of nonlinear wave decay over a fluidized bed in coastal waters were investigated by applying the HHT method to analyze the measurements from wave flume experiments. The Ensemble EMD (EEMD) was adopted to decompose the wave and pore pressure data into the intrinsic mod functions (IMF). In a resonantly fluidized response, the results of Hilbert amplitude spectrum of waves derived by the HHT illustrate that wave decay obviously occurs mainly on the fundamental component. In following non-resonantly fluidized tests, the wave decay becomes relaxed with thinner fluidized-layer. Furthermore, the wave decay is immediately due to fluidized response, but the decay along propagation over a fluidized bed is relatively insignificant. The wave-decay ratio is found to be directly proportional to the magnitude of Ursell number (Ur).