In accordance with at least some embodiments, a computer system includes an enclosure (202) configured to hold at least one resource unit (204). The computer system also comprises a plurality of mixed-flow ducted fans units (400) selectively attached to the enclosure (202). Each mixed-flow ducted fan unit (400) comprises a duct (102) having an intake diameter, a bellmouth diameter, and an exhaust diameter. The bellmouth diameter is less than the intake diameter and the exhaust diameter.