A measuring method to detect wall flow Tofu topologies by active infrared thermography was developed.Quadcopter rotor blades were studied in typical hover and forward flight conditions, while using a high-power infrared laser to heat the blade surface.By this, the distance between heat source and measuring object could be significantly increased compared to conventional heat sources.
The resulting images show little blurring at high signal-to-noise ratios.In steady-state flow conditions, wall flow topologies could be detected reliably and show good agreement with performed oil-film interferometry measurements.Wind tunnel experiments at forward flight conditions were CPAP Masks conducted and indicate unsteady shifts of the transition location.