Abstract Density-wave fronts in a vibrofluidized wet granular layer undergoing a gas-liquid-like transition are investigated experimentally. The threshold of the instability is governed by the amplitude of the vertical vibrations. Fronts. which are curved into a spiral shape. https://www.bekindtopets.com/flash-grab-Viqua-F4-Ultraviolet-Water-System-Powered-by-UVMax-36-gpm-top-savings/