A valve includes: a tubular pipe section, a first flat plate extending transversely to the pipe section inside the pipe section and secured to the pipe section, this first flat plate being pierced with a central orifice and with a plurality of peripheral orifices positioned circumferentially around the central orifice, a second flat plate extending transversely to the pipe section inside the pipe section and mounted with the ability to rotate inside the pipe section, the second plate having a plurality of orifices of which at least the shape and the spacing correspond to those of the orifices of the first plate, at least one support element supporting the second plate such that the at least one support element can pivot with respect to the first plate, and an adjusting system engaging with the second orifice plate in order to adjust the relative positions of the peripheral orifices.