# Density-wave fronts on the brink of wet granular condensation

## TL;DR

This paper experimentally investigates density-wave fronts in a vibrofluidized wet granular layer near a gas-liquid transition, revealing how vibration amplitude influences pattern formation and stability.

## Contribution

It introduces a model explaining pattern formation through competition between condensation and energy injection time scales in wet granular systems.

## Key findings

- Density-wave fronts propagate along the container rim.
- Front stability depends on distance from the container center.
- A proposed model links pattern formation to condensation and energy injection dynamics.

## 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, propagate coherently along the circular rim of the container with leading edges. They are stable beyond a critical distance from the container center. Based on an analysis of the emerging time and length scales, we propose a model for the pattern formation by considering the competition between the time scale for the condensation of wet granular particles from a gas-like state and that of the energy injection resisting this process.