Development of Laboratory Facilities for Evaluation of Drag-Reducing 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 implemen- tation of riblet surfaces which refers to small scale, stream-wise structures which tailor the turbulent boundary layer in a way that reduces viscous drag. A new low-speed wind tunnel designed specially for these experiments has been constructed and characterized using a variety of measurement techniques including a new iteration of a skin-friction balance. The result is a facility that produces well behaved flow with incorporated instrumentation that is suited for the future evaluation of drag reduction surfaces.