Pressure Sensitive Paint

ARA is continually examining the performance of advanced measurement technologies in order to improve the testing capability available in the Transonic Wind Tunnel (TWT).

The Pressure Sensitive Paint (PSP) technique provides many benefits, including the following:

1.   It removes the need for a large number of pressure tappings which:

• Reduces the duration of model design and manufacture.
• Reduces the cost of the model.
• Allows pressure measurement in areas inaccessible to pressure tappings.
• Increases model integrity.

2.   It provides spatial pressure distributions which can identify flow features that would be very difficult to measure satisfactorily using pressure tappings.

3.   It is possible to integrate the acquired pressure fields over the region of interest to determine, for example, accurate control surface hinge moments.  This cannot be achieved using pressure tappings and the associated connection tubes.  PSP can remove the need for hinge moment balances.  

For this reason the status of the PSP technique has been closely monitored and it has now reached a level of maturity to warrant examination under production wind tunnel testing conditions.

A series of tests to evaluate the performance of PSP has been successfully completed in the TWT and typical results are shown above.  The success of this test programme has demonstrated the advantages of the use of PSP in wind tunnel testing.