Wind tunnel study of the boundary layer

• A centrifugal fan is mounted inside a plenum. It is equipped with a rechargeable filter, a honeycomb for straightening the flow and a mesh grid to reduce residual turbulence.
• A two-dimensional plexiglass convergent, with a contraction ratio of 30, ensures a good homogeneity of speed at the outlet of the jet.
• A simple air bypass valve system provides progressive and precise adjustment of the jet outlet speed.
• The jet is channeled by two vertical walls in transparent plexiglass. One of the two walls, mounted on hinges, provided with a locking device in the open position, facilitates the interventions inside the test line.
• A traversing device, consisting of a carriage mounted on ball bearings, can be moved along the test line. Its positioning is carried out using an index and a graduated scale fixed on the frame of the test vein.
• The traversing device allows the vertical displacement of the probes in the median plane of the test vein. The positioning of the probes is carried out thanks to a graduated vernier. A quick fastening device allows the mounting of probes of different diameters.
• A boundary layer probe is provided as standard.
• Study of the development of the boundary layer in the case of a plane parietal jet
• Study of speed profiles
• Determination of laminar and turbulent boundary layers
• Search for a dimensionless profile and invariants
• Study of the local coefficient of friction
• Study of mass flows and momentum
• Search for dimensionless invariants

Specific Experiments in Hot Wire Anemometry with Optional EV240
Calibration of hot wire
Verification of King's Law
Study of the influence of the orientation of the probe with respect to the main airflow
Initiation to turbulence measurements
Measurement of the turbulence intensity of a free jet and a boundary layer
Determination of the turbulence spectrum for different Reynolds numbers