Gravitational spreading of granular paste droplets induced by mechanical vibrations

Spreading experiments of granular paste droplets over a smooth and hydrophilic plate under vertical vibrations were performed. We show that applying vibrations tunes the spreading by changing the apparent viscosity of the paste and makes a Newtonian regime appear where R ( t ) ∝ t 1/8 . In this regime, the influence of the intensity of the vibrations, the diameter of the particles and the interstitial viscosity is investigated, and all experiments are rationalized by a lubrication Peclet number, in agreement with previous results from the literature. Vibrations allow the spreading of granular paste to be tuned by controlling its apparent viscosity.