The hydrodynamic behaviour of the submerging jet from nozzle in particulate medium by determining the velocity profiles is investigated in a 500 mm x 250 mm column filled with sand particles of 230 mu m mean diameter and 2576 kg/m(3) density. The upflow jet air emerges from a nozzle with 15 mm diameter. Three nozzles with lengths of 80, 40 and 0 mm from above the distributor are used. The experiments show that the jet fundamental properties and the self-similarity of the reduced velocity profiles remain constant in the process. The self-similarity of the reduced velocity profiles is thus an intrinsic property in the steady-state flow of the jets in a particulate medium, whatever the longitudinal axis, the length of the nozzle, the jetting velocity and the bed state (aerated or fluidized). (c) 2008 Elsevier B.V. All rights reserved.