Measurements of the sampling volume of an infrared laser doppler velocimeter for the study of feasibility of simultaneous three-dimensional velocity profile mapping
Abstract
High resolution incoherent mapping of the sampling volume was performed to determine the three dimensional profile of the volume of the beam from which information can be obtained by scattering. The incoherent sampling volume of the infrared laser Doppler velocimeter was found to be heavily dependent upon the configuration of the outgoing laser beam. In general when only half the beam is allowed to focus at the focal plane, the x, y traverses indicate a broader beam with nominal side lobes. However, if the total beam is permitted to impinge on the focal plane there is substantial narrowing of the beam with increased maximum intensity and an increase in side lobes. The double maximum indicated by the coherent sampling volume appears to be an artifact of the scanning process not a fundamental entity of the sampling volume.
- Publication:
-
In Alabama Univ. Res. Rept.: The 1980 NASA/ASEE Summer Fac. Fellowship Program 26 p (SEE N81-11977 02-99
- Pub Date:
- October 1980
- Bibcode:
- 1980asee.nasaS....B
- Keywords:
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- Infrared Lasers;
- Laser Doppler Velocimeters;
- Three Dimensional Flow;
- Velocity Distribution;
- Electro-Optics;
- Focal Plane Devices;
- Heterodyning;
- Incoherence;
- Laser Outputs;
- Orthogonality;
- Signal To Noise Ratios;
- Lasers and Masers