A fluid mixing device (1) includes a chamber (3) and a bluff body (4) defining one end of the chamber (3). A first fluid inlet (5) is located toward an opposite end of the chamber (3) from the bluff body (4) and arranged to direct fluid toward the bluff body (4). A region substantially surrounding the bluff body (4) has a flow divider (8) defining second fluid inlet(s) (11) to the chamber (3) and mixed fluid outlets (12) from the chamber (3). A fluid flow from the first fluid inlet (5) and/or from the second fluid inlet (11) establishes a recirculating vortex system (14) within the chamber and results in a mixture of fluids from the first fluid inlet (5) and the second fluid inlet(s) (11) being directed through the mixed fluid outlets (12).