In the present work the structure of the gas velocity-field of a nonevaporating diesel spray and its time evolution have been studied. A two-component PDA is used to measure ensemble-averaged spatial distributions of droplet size, axial, and radial velocities. Measurements are taken during Very short temporal windows along many injection cycles. Spray droplets with sizes under 5 mum are used as tracers of the gas velocity field. A vortex is identified in the gas-phase velocity field at the periphery of the spray. A simple methodology based on a Rankine vortex model enables one to characterize the structure and its time evolution.