3.1 Subsonic Wind Tunnels for Aeronautics
61
3.1.6 Pressurised Subsonic Wind Tunnel
Operational since 1974, the F1 wind tunnel at ONERA, Fauga-Mauzac is a closed
circuit wind tunnel with a rectangular test section of a cross-section of 4.5 m by
3.5 and 11 m long (see Fig. 3.15). Pressurisation of the installation (up to 3.85 bar)
increases the density of the flow in order to maintain a high Reynolds number to
compensate for the reduced size of the model compared to the full scale vehicle.
The F1 power-plant is a 16-blade, constants-speed fan driven by a 9.5 MW electric
motor. Mach number is adjusted by changing the pitch angle of the blades. The flow
maximum velocity is 123 m/s (Mach 0.36) at a stagnation pressure of 1 bar, this
maximum value decreasing when the stagnation pressure is increased (see Fig. 3.16).
It is not possible to achieve a factor greater than 4 on the Reynolds number by
pressurisation, the dynamic forces on the structures (walls, floors) becoming then
too significant. In addition, since the aerodynamic forces being also increased by the
same proportions, excessive deformation of the model and a possible failure of its
support could be experienced.
The test section and its cylindrical casing are mounted on carts detachable and
movable allowing for rapid changeover and testing of configurations already mounted
and prepared in three other interchangeable sections equipped with a data acquisition
unit.
Fig. 3.15 General arrangement of the F1 wind tunnel of the ONERA Fauga-Mauzac centre
(© ONERA)
61
3.1.6 Pressurised Subsonic Wind Tunnel
Operational since 1974, the F1 wind tunnel at ONERA, Fauga-Mauzac is a closed
circuit wind tunnel with a rectangular test section of a cross-section of 4.5 m by
3.5 and 11 m long (see Fig. 3.15). Pressurisation of the installation (up to 3.85 bar)
increases the density of the flow in order to maintain a high Reynolds number to
compensate for the reduced size of the model compared to the full scale vehicle.
The F1 power-plant is a 16-blade, constants-speed fan driven by a 9.5 MW electric
motor. Mach number is adjusted by changing the pitch angle of the blades. The flow
maximum velocity is 123 m/s (Mach 0.36) at a stagnation pressure of 1 bar, this
maximum value decreasing when the stagnation pressure is increased (see Fig. 3.16).
It is not possible to achieve a factor greater than 4 on the Reynolds number by
pressurisation, the dynamic forces on the structures (walls, floors) becoming then
too significant. In addition, since the aerodynamic forces being also increased by the
same proportions, excessive deformation of the model and a possible failure of its
support could be experienced.
The test section and its cylindrical casing are mounted on carts detachable and
movable allowing for rapid changeover and testing of configurations already mounted
and prepared in three other interchangeable sections equipped with a data acquisition
unit.
Fig. 3.15 General arrangement of the F1 wind tunnel of the ONERA Fauga-Mauzac centre
(© ONERA)