Deformation of drops at low Reynolds number impact

Drop impact experiments are performed with very viscous fluids to propose a description of the drop deformation at low Reynolds number. We focus on a specific case where dimensionless parameters other than the Reynolds number play no role, which means that only kinetic energy and viscous dissipation determine the final deformation. The same situation in the case of a Reynolds number larger than ten has been clarified years ago. The maximum diameter of the spread drop is well described by a 1/5 power law of the Reynolds number only. Here the deformation of the drop, defined as the contact diameter rescaled by the drop size, is also a power law of the Reynolds number. From experimental data and scaling arguments, the exponent of the power law is shown to be 1/3.