Abstract A filtrational flow in a regular packed bed is arranged so that it allows both direct measurement of the velocity distribution in the layer and flow visualization. Detailed diagrams of mean velocities and the flow turbulence levels, as well as one-dimensional spectra of longitudinal velocity pulsations, have been obtained using LDA for an optically transparent system of glass spheres and a special immersion system. Reynolds numbers, calculated from the sphere diameter and the flow velocity in a minimal cross-section between the spheres, are in the range 1000–20,000. It has been established that the flow past a regular array of spheres is of jet character. The flow past the contact points of spheres results in a local flow separation, the value of such a separation zone being mainly dependent on the method of sphere packing. On the basis of the experimental results, the turbulence generation mechanism in regular arrays of spheres is presented.