The institute operates a large low-speed wind tunnel. The tunnel is installed over two subsurface floors. The gross dimensions of the tunnel are (2x)42m in length, 5.5m in width and 10.5m in height. It is equiped with a 400kW blower with adjustable pitch blades.
The tunnel provides an excellent facillity for the aerodynamic analysis of ship super-structures, scaled vehicles, sport-equipment, vehicle and aircraft components, heat exchangers, aerodynamics of buildings etc. at low to moderate speeds.
Test Section Dimension
The tunnel features a 5.5m long open test section. The test section features manual and optical access from the top and the two lateral sides. The floor is connected to the exit plane of the nozzle and the entrance plane of the collector. Positioning of intrusive and non-intrusive measurement sensors is supported by a multiple-axes traversing system mounted to the lateral sides of the section.
The test section can optionally be closed partly (along selected sides). The maximum cross section of the test section is 3m x 2m. A second nozzle which contracts to a 2m x 2m cross section can be mounted to the settling chamber.
The test section is usually mounted aft of the nozzle, but can also be swapped with subsequent section to allow the build up of a boundary layer.
Operating Speeds - Flow Uniformity & Turbulence Intensity
The tunnel operates at approximately 5m/s - 35m/s for the 3m x 2m test section. In conjunction with the smaller 2m x 2m test section a maximum speed of 45m/s can be achieved.
The turbulence intensity is below 0.3%. The flow non-uniformity of the velocity and temperature are below 0.1% and below 1% respectively.
The tunnel is usually operated in a closed circuit loop, called "Göttingen" mode.
In case of flow visualisation and smoke test, it can also be operated in an open (aka. "Eiffel") mode, where external air is supplied to the blower section and the air stream is released from the tunnel aft of the test section through an opening to the ambient air.
Data Acquisition and Measurement Techniques
The tunnel has computerised control system. A modern state-of-the-art data-processing software and computing hardware supports to make maximum use of the facility.
The wind tunnel is equipped with a motion simulator. The model is coupled to 8 computer-controlled sleds by a wire suspension which forces it to free adjustable motions at 6 degrees of freedom. The model itself is designed as a 6 component balance for measuring the forces and moments on the moving model. Performance parameters of the motion simulator are
max. model dimension: LxBxD: 4500mm x 1000mm x 1000mm
max. model weight: 100 kg
combined motions at 6 degrees of freedom
translations: max. amplitude: 0.5 m
max. frequency: 0.5 Hz
rotations (yaw and pitch axis): max. amplitude: 5 deg
max. frequency: 0.5 Hz
A number of measurement techniques for the acquisition of fluiddynamic quantities are available. Measurable values are pressure by means of static/dynamic pressure probes
- velocity by means of non-intrusive 3-component (stereoscopic) PIV
- images for 0.5m x 0.5m wide planes (15 frames / second)
- 4MP image resolution
- flexible positioning of observed plane using a light arm and a traversing system
- velocity measurements non-intrusive turbulence-resolving LDA
- velocity measurements using hot-wire probes
- optical determination of model position and model deformation under wind loads
- an integrated 6-component (external) balance which supports
- models featuring a maximum weights of 150kg to 250kg
- operation in two different kinematic configurations (to adjust to different load levels)
- max. forces of 200N to 400N and max. moments of 200Nm
- ballance connected to a flush-mounted turning table which allows for 360° rotation of models and supports rapid analysis of approach-angle influences
- video recordings