Propagation and attenuation of surface waves and pressure waves in a fluidized bed with a vibrating plate

A fluidized bed with a surface wave generator was utilized to investigate pressure wave sources, propagation, and attenuation. The results indicated at least three distinct waves within the fluidized bed, i.e., surface waves originating from the movement of the bed surface, reflected surface waves from the wall, and the elastic waves resulting from the compression of the particulate phase in the vicinity of the plate. The attenuation rate is related to the intricate interplay of these pressure waves within the bed. Pressure waves propagate both horizontally and vertically within the bed. In the horizontal direction, surface waves are the dominant pressure waves at low frequencies, and the surface waves are no longer the dominant components of the pressure waves at high frequencies. The surface waves are not dominant in vertically propagating pressure waves. The vibrating plate impedes the transmission of the reflected wave in the vertical direction. • Origin, propagation and attenuation of pressure waves were studied. • Surface waves, reflected surface waves, and elastic waves were identified. • Surface waves are not always dominant pressure waves in fluidized beds. • Pressure waves propagate and get attenuated in all directions.