Grant: Research Tools and Instruments

Airfoil noise is the canonical aeroacoustic problem for any wall-bounded noise sources, stemming from any transportation system, or any ventilation and power generation systems. For instance, it directly contributes to the prediction and control of low and high speed fan noise and of airframe noise generated by high lift devices or empennages. As such, airfoil noise responds to important present and future environmental and health issues related to increasing air traffic, proliferation of autonomous vehicles and noisy work conditions. Within the framework of three consecutive Industrial Chairs, the Aeroacoustic research group at Université de Sherbrooke (UdeS) has developed a solid expertise on airfoil noise contributing to state of the art numerical simulations that have unveiled several new noise mechanisms and guided the development of several fast analytical models. The latter can then be used at a pre-design stage of any rotating machine and are now integrated in a complete unique software platform that is being commercialized. Yet, any of this virtual development requires a detailed experimental validation that can be achieved in the aeroacoustic wind tunnel at UdeS, a unique test facility in Canada. Such a validation procedure not only involve acoustic measurements with arrays of microphones to provide insight on the noise source directivity and the actual source localization, but also several flow measurements ranging from pressure measurements with remote microphone probes to local hot-wire anemometry with multiple wire probes, and global field anemometry by Particle Image Velocimetry (PIV). The latter has been shown to provide valuable information on the three dimensional turbulent velocity field around the airfoil trailing edge, and therefore the associated noise sources. The present proposal is then meant to maintain and extend such a capability by providing the research group with a more robust laser and an upgraded postprocessing PIV software, which should able the experimental aeroacoustic group at UdeS to catch up with the number of simulations already achieved by the group. It should also allow the group to apply the same technique to larger fields of view and to more complicated experimental setups such as complex and complete heat, ventilation and air conditioning modules as studied in the parallel Consortium for Ultra HighEfficiency and Quiet Fans and in the Collaborative Research Project on electrical cooling and air conditioning modules within electrical vehicles. This will provide an unprecedented database and valuable information to yield quieter solutions for such systems.