4.3 Typical Transonic Wind Tunnels
103
Fig. 4.7 Test section of the ONERA S8Ch wind tunnel with a second throat (© ONERA)
4.3 Typical Transonic Wind Tunnels
4.3.1 Very Large Transonic Wind Tunnel
The very large S1MA transonic wind tunnel at ONERA, Modane-Avrieux shown
by the 3D assembly drawing in Fig. 4.8, is equipped with two 15 m diameter counterrotating fans with 10 and 12 blades with adjustable pitch. These fans are driven by
Pelton turbines with a capacity of 44 MW each.
The turbines that drive the fan are supplied with 10 million cubic meters of water
per year from several reservoirs managed by EDF (Electricity of France). From the
dam above Avrieux in the Alps, a waterfall of 840 m high provides the energy to drive
the wind tunnel through a penstock sluice where the flow rate can reach 15 m
3 /s. The
cooling of the wind tunnel is ensured by exchange of air with the atmosphere through
air vents. The test section has a diameter of 8 m and a length of 14 m, making S1MA
the largest transonic wind tunnel in the world. The wind tunnel has 3 interchangeable
test sections mounted on trolleys to ensure ease of model change-over and rapid
turnaround for testing various configurations (see Fig. 4.9).
One of the test sections may be equipped with solid or slotted walls/liners. The
Mach number is continuously adjustable from 0.05 to 1 by varying the rotation speed
of the fans from 25 to 212 rpm. The total pressure is approximately equal to the local
atmospheric pressure; i.e., 0.9 bar, the stagnation temperature being between 258
103
Fig. 4.7 Test section of the ONERA S8Ch wind tunnel with a second throat (© ONERA)
4.3 Typical Transonic Wind Tunnels
4.3.1 Very Large Transonic Wind Tunnel
The very large S1MA transonic wind tunnel at ONERA, Modane-Avrieux shown
by the 3D assembly drawing in Fig. 4.8, is equipped with two 15 m diameter counterrotating fans with 10 and 12 blades with adjustable pitch. These fans are driven by
Pelton turbines with a capacity of 44 MW each.
The turbines that drive the fan are supplied with 10 million cubic meters of water
per year from several reservoirs managed by EDF (Electricity of France). From the
dam above Avrieux in the Alps, a waterfall of 840 m high provides the energy to drive
the wind tunnel through a penstock sluice where the flow rate can reach 15 m
3 /s. The
cooling of the wind tunnel is ensured by exchange of air with the atmosphere through
air vents. The test section has a diameter of 8 m and a length of 14 m, making S1MA
the largest transonic wind tunnel in the world. The wind tunnel has 3 interchangeable
test sections mounted on trolleys to ensure ease of model change-over and rapid
turnaround for testing various configurations (see Fig. 4.9).
One of the test sections may be equipped with solid or slotted walls/liners. The
Mach number is continuously adjustable from 0.05 to 1 by varying the rotation speed
of the fans from 25 to 212 rpm. The total pressure is approximately equal to the local
atmospheric pressure; i.e., 0.9 bar, the stagnation temperature being between 258