High-Quality Skin Friction Measurements in 2-D Flows Using Oil Film Interferometry

The application of Oil Film Interferometry to three two-dimensional flows is discussed. Specifically, the use of OFI on a hump mounted on a splitter plate, in a wall jet, and on the floor of a boundary layer wind tunnel is presented. These three cases demonstrate the wide range of demands that can be placed on the measurement technique and, in all cases, good quality measurements have been achieved. The one-image analysis technique used to analyze all of the interferograms obtained here is briefly presented. Result from all three cases are then presented and discussed. The objectives of these different tests vary widely from CFD validation to instrumentation development and validation to facility characterization. These results indicate that, at least in two-dimensional flows, OFI may be used effectively in a wide rage of settings. Due to the value of such measurements, I believe that these measurements should become more widespread in the future. Areas for future development are also suggested.