Development of High Speed Interferometry Imaging and Analysis Techniques for Compressible Dynamic StallThe development of a high-speed, phase-locked, realtime, point diffraction interferometry system for quantitative imaging unsteady separated flows is described. The system enables recording of up to 224 interferograms of the dynamic stall flow over an oscillating airfoil using a drum camera at rates of up to 40 KHz controlled by custom designed electronic interlocking circuitry. Several thousand interferograms of the flow have been obtained using this system. A comprehensive image analysis package has been developed for automatic processing of this large number of images. The software has been specifically tuned to address the special characteristics of airfoil flow interferograms. Examples of images obtained using the standard and the high-speed interferometry techniques are presented along with a demonstration of the image processing routine's ability to resolve the fine details present in these images.
Document ID
19980204006
Acquisition Source
Ames Research Center
Document Type
Conference Paper
Authors
Chandrasekhara, M. S. (Naval Postgraduate School Monterey, CA United States)
Carr, L. W. (NASA Ames Research Center Moffett Field, CA United States)
Wilder, M. C. (MCAT Inst. San Jose, CA United States)