Major Instrumentation

Force Measurements

Lift Balance

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 forces.

Instrumented Framework

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:

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).

Flow Measurements

Pressure Transducers

Models can be instrumented with pressure transducers to measure the pressure distribution around them. Two types of pressure measurements are available :

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 interest.

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.

Data Acquisition

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.