Non-obtrusive detection of transition region using an infra-red camera
Abstract
A Mach 3.85, high Reynolds' Number flow in a 5 x 5-inch blowdown wind tunnel was used to determine the region of natural transition on a flat model, by recording the infrared emission from the plate surface. The respective chord and span dimensions of the plate were 7.5 and 5.0 inches, and a bakelite insulator was incorporated as the test surface. The tests were conducted with an airfoil stagnation temperature close to atmospheric (33 C.). The recovery temperatures at the plate surface thus derived from the infra-red camera measurements, for the case of negligible heat transfer and pressure gradient, defined the extent of transition. The more conventional transition diagnostic techniques utilizing sublimation patterns, a surface pilot tube and surface hot-film gauges, supported the infrared measurements.
- Publication:
-
In AGARD Laminar-Turbulent Transition 17 p (SEE N78-14316 05-34
- Pub Date:
- October 1977
- Bibcode:
- 1977ltt..agarR....P
- Keywords:
-
- Flat Plates;
- Infrared Detectors;
- Transition Flow;
- Transonic Wind Tunnels;
- Airfoils;
- Blowdown Wind Tunnels;
- Reynolds Number;
- Surface Temperature;
- Fluid Mechanics and Heat Transfer