The invention relates to a machine through which a main flow (E) of water passes, including a turbine wheel (4), with at least a turbulent zone, reduced-pressure zone or cavitation zone (8, 10, 33) being formed close to said wheel. The wheel includes blades (6) disposed between a ceiling (28) and a belt (30). The machine also includes means for injecting a flow (E2) drawn from the main flow into the aforementioned zone (8, 10, 33) such as to alter the main flow (E) locally or increase the pressure in said zone (8, 10, 33). Said injection means inject the drawn flow (E2) from the ceiling (28) or from the belt (30) through holes (31, 32) provided in the ceiling (28) or belt (30).