Laser Doppler anemometer diagnostics in unsteady flows
Abstract
The application of the laser Doppler anemometer (LDA) to unsteady flows is discussed with respect to necessary features of the signal processor, properties of the optical system, and the character of the flow under investigation. The discussion of signal processors includes consideration of frequency trackers, counter-type processors, particle properties, data rates, and statistics. Secondly, diffraction limitations for an optical system are viewed with respect to spatial resolution. Finally, the total velocity field is decomposed into its subfields and the feasibility of, criteria for, and possible types of conditional sampling are defined. Several reported LDA experiments using conditional sampling are presented to demonstrate the different techniques that may be used.
- Publication:
-
Dynamic Measurements in Unsteady Flows
- Pub Date:
- 1979
- Bibcode:
- 1979dmuf.proc..511O
- Keywords:
-
- Flow Measurement;
- Laser Doppler Velocimeters;
- Unsteady Flow;
- Flow Characteristics;
- Optics;
- Signal Processing;
- Velocity Distribution;
- Instrumentation and Photography