Abstract: An apparatus for generating at least one oriented jet of gaseous fluid that is movable in a direction substantially perpendicular to this orientation is provided, the apparatus including a hollow box (3), in particular a rectangular parallelepiped with rigid walls (3a), at least one flexible belt (7), which sealingly closes each aforementioned window (5) vertically of its edges (6), and which locally has at least one perforation (8) of predetermined dimensions, a driver for each belt (7) for driving the belt along the longitudinal axis (5a) of the window (5) vertically of which it is located, in such a manner as to displace each perforation of the belt in question along the longitudinal dimension of the window, and an injector for injecting gaseous fluid, in particular air, into the box (3) through an opening (11) made in one of its walls.