Quiet Flow Facility (QFF)

The Quiet Flow Facility (QFF) is an anechoic open-jet facility that was designed specifically for acoustic testing. The anechoic chamber surrounding the free jet has dimensions of 9.1 m (30 ft) x 6.1 m (20 ft) x 7.6 m (31.5 ft) high as measured from the acoustic wedge tips. The free jet exhausts vertically through an acoustically treated exhaust port in the chamber ceiling.

Flow-circuit turbulence screens and turning vanes have been included to ensure low turbulence airflow. The entire anechoic room is mounted on springs to isolate it structurally from the rest of the building to minimize transmission of structure-borne noise into the facility.

In addition to the acoustic testing capabilities, the facility can also be configured for flow survey measurements using 3-Component Particle Image Velocimetry (3-C PIV) and or probes such as hot-wires. Maximum Mach numbers of the facility vary depending on the inlet nozzle selected. A maximum Mach number of 0.9 can be reached if a 0.3048 m (1 ft) diameter nozzle is used.