The lift balance consists of a circular plate carried by a four-arm structure.
The latter is fixed to a traction/compression force transducer to measure the vertical force (lift force). This balance measures
only the lift force. The equipment sits below the ground wall of the tunnel, in the rotating test table.
The whole system is outside the airflow. The maximal vertical force is 2500N.
Aerodynamic Balance Pylon
The aerodynamic pylon consists of an instrumented beam with circular cross-section. The strain
gauges are arranged in a Wheatstone bridge to measure the deformations in 2 orthogonal directions.
Using the aerodynamic pylon with the lift balance allows the measurement of lift, drag and sideslip
The University has designed and built an instrumented framework structure. It is installed inside the
airflow, in the vicinity of the tunnel walls. The structure is adaptable to the dimensions of the model.
Its main purpose is to allow vertical and streamwise degrees of freedom. The model is guided in those
directions via compressed air bushes, which ensure minimal friction contact. The model is also free to
rotate around its rotation axis thanks to two ball bearings on both sides of the model. This setup
allows two types of measurements:
- Static measurement of forces and couples acting on the model.
- Dynamic measurement of the movement of the model.
6-axis force/torque sensor for small loads
An ATI six-axis force/torque sensor system can be used for measuring small loads (up to 12N
lift, 8N drag). This instrument is ideal for small models at low airspeeds and has particular
applications in biomechanics (e.g. aerodynamic load measurements on bat models).
Models can be instrumented with pressure transducers to measure the pressure distribution around
them. Two types of pressure measurements are available :
- A 64-channel PSI Pressure Scanner. This pressure transducer possess its own acquisition software
- A 18-channel simultaneous pressure measurement device. These pressure transducers are connected to a
NI PXI-1010 data acquisition module. The pressure range of these transducers is 0-30 KPa (relative pressure).
Particle Image Velocimetry (PIV)
The velocity distribution around a model can be measured in test section TS1 using a Dantec Dynamics rapid
Particle Image Velocimetry system. The capabilities of the system are :
The laser lies on a translation system which enables the positioning of the laser sheet in the zone of
- 2D visualization of the flow field around any model;
- up to 1600 frames per second (depending on the visualization window size);
- window size up to 1612 pixels by 1200 pixels, corresponding to 15 by 15 cm;
- oil particle seeding (diameter of 10 μm)
Hot Wire Measurements
Local flow velocities in the test section can be measured using hot wire probes. The probes can be
driven from outside the test section to measure velocities over a vertical plane. This instrumentation
is also used to measure and validate the turbulence level in the atmospheric boundary layer. The
available system is the Stream Line CTA of the DANTEC Dynamics company.
A National Instruments NI PXI-1010 data acquisition and amplification module is available. It
features 8 channels for voltage signal acquisition (such as conditioned accelerometer signals) and 32
channels for strain gauge signal acquisition.