US Patent 10385877 Fluid machine

A fluid machine includes a rotatable hub; a plurality of blades spaced apart from one another along a circumferential direction with respect to a rotation center of the hub; and a shroud extending along a circumferential direction with respect to the rotation center of the hub and covering the plurality of blades. The shroud includes: a flow passage, the flow passage formed to be recessed with respect to an inner surface of the shroud facing the blades; and a plurality of resonators provided in the flow passage.