Applications of Laser Doppler Techniques for Measurements in Large Flow Systems

摘要

The objective of the study was to develop the theoretical and experimental knowledge necessary to utilize the laser Doppler velocity measurement technique in large flow systems. Theoretical treatments were developed to allow prediction of the capabilities and limitations of the laser Doppler technique as applied to (1) use in the backscatter mode with no artificial contaminants in the flow; (2) localization of the measurement volume and its effects on the measurement of turbulence phenomena; and (3) degradation of the heterodyning efficiency due to long path lengths in optically inhomogeneous media. Experimental confirmation of theoretical predictions were carried out to demonstrate validity or to establish an experimental technique. (Author)