An assembly for converting a fluid flow includes a housing having an inlet end for receiving the fluid flow and an outlet end for issuing a converted and output fluid flow. One or more rotatable components are supported within the housing, in a path contacting the inlet fluid flow. A selected component exhibits a plurality of arcuate and flow conducting surfaces, such as which are arranged about a circumference of the rotating component. A fluid dampening element is operatively connected to the rotating component and restricts a rotational speed associated with the rotatable component, in response to rotational forces imparted by the inlet fluid flow, and in order to modify at least one of a flow and pulse rate of the fluid.