Design and fabrication of a low-speed wind tunnel for evaluation of drag reduction surfaces

Laboratory scale evaluation of various drag reduction surface morphologies can provide valuable insight on their capabilities for both design optimization and as-built performance verification. Specifically, the primary drag reduction technique evaluated here is the implementation of riblet surfaces which refers to small scale, streamwise structures which tailor the turbulent boundary layer to reduce viscous drag. Ongoing work between multiple collaborating parties at the University of Wyoming has established the abilities to both produce and measure the performance of these riblet surfaces. Here, the design and construction of a new wind low-speed tunnel specifically intended for these experiments is discussed and preliminary characterization of the tunnel is shown. Care has been taken to design a tunnel optimized for producing appropriately scaled boundary layers to test riblet surfaces manufactured by the same methods intended for in-field use on aircraft.