ARA Gust Rig Capability Proven in Wind Tunnel Tests
With the drive for design optimisation, lower weight and lower fuel burn, a major challenge facing the aerospace industry is to better understand the structural design required to minimise the effects of dynamic load conditions on aircraft flight characteristics. To optimise structural design there is a need to understand the dynamic loads aircraft will experience, which requires the ability to replicate them in a controlled manner and measure the effects. The ARA Gust Rig was designed and constructed to generate the necessary conditions to simulate the vertical gust loading that is experienced by aircraft in transonic cruise which meet the FAA and EASA regulatory requirements – the first large scale rig in the world for these conditions.
The ARA Gust Generation Rig consists of two specially designed vanes installed upstream of the tunnel test section. Each vane comprises of 900 air solenoid valves which produce an oscillatory movement of air, controllable in shape, magnitude and speed, thus introducing a dynamic change in angle of attack seen by the aircraft model in the tunnel.
Following a large amount of development work after the initial trials in 2014, two tests have been conducted in 2017 to optimise the rig operation and performance. The first was to characterise the gust rig performance in detail and to achieve this more than 1500 different gusts were fired to assess the production, control and repeatability of varying temporal and spanwise profile, gust magnitude and Mach number. A rake was installed in the test section to measure various gust parameters using a range of instrumentation.
The results from these tests were used to develop and complete the gust mathematical model and control software. The second test with a semi-span model installed in the test section was used to validate the gust control algorithm and provide measured data for comparison with CFD software. Dynamic Pressure-Sensitive Paint (DPSP) and Dynamic Model Deformation Measurements (DMDM) were used to provide additional diagnostic measurements to assist in the data analysis.
Whilst the analysis of the data is still ongoing, the two tests have shown that the rig is providing the range of test conditions for which it was designed and that this is now a capability which can be used at ARA by our customers.