An aerodynamical mechanism for droplet splashing

Using a numerical study of drop impact on a solid substrate, we propose an aerodynamical mechanism to explain the dependance of the impact on the gas properties. Varying both the viscous and density ratio between the drop liquid and the external gas in the incompressible limit, we describe the frontier between spreading and splashing. Although a jet is sometimes formed before contact, we show that the splashing dynamics is controlled by the aerodynamical pressure exerted by the gas on the expanding liquid sheet.