The Optical Towing Tank for Energetics Research (OTTER) is a testing facility located in McLaughlin Hall at Queen’s University. Acquired from the National Research Council of Canada (NRC) in 2014, the facility is designed for high Reynolds number testing with applications in aerospace, defence, and renewable technologies. Although models are scaled down in size, the use of water over air in a wind tunnel allows for higher Reynolds numbers to be reached. Submerged models move by a motorized carriage system across the 15 m length of the tow tank, with a 1 m by 1 m cross-section capable of reproducing both steady and dynamic flow conditions through carriage motion. The models may be instrumented to record force and surface pressures, and can be further manipulated (e.g., pitching and surging of an airfoil) during their motion. Optical flow measurements, such as particle image velocimetry (PIV), are also possible using cameras and lasers mounted on two other traverse systems beside and below the facility, that are synchronized to the model motion. These results facilitate wake analysis behind the towed model, and combined with simultaneous model force and pressure measurements, allow for better understanding of the underlying flow physics.

OTTER has been utilized within our research group for many different testing purposes, most notably for wind turbine and solar panel research projects. The facility has been used to test turbines, airfoils, and flat plate models when exposed to unsteady aerodynamic conditions at high Reynolds numbers, such as change in wind direction or speed. OTTER is currently undergoing upgrades to its propulsion system with the goal of being able to safely reach higher towing speeds and accelerations.