Nomograms for the Doppler Shift Velocimeter
ARNOLD ENGINEERING DEVELOPMENT CENTER ARNOLD AFB TN
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The preliminary design of a laser Doppler velocimeter LDV for a particular application requires the determination of the frequency-to-velocity conversion constant and the spacial resolution of the focal volume. These parameters give the frequency range required of the signal processing electronics and the size of the region in which velocity measurements are being made. These values are determined from the laser wavelength, the focal length of the focusing lens, the angle of the LDV beam pair intersection, and the diameter of the focused beams at the intersection. A set of nomographic scales has been developed to allow rapid and accurate determination of these parameters. They are also particularly useful in evaluating the effects of parameter variation and optimization of the LDV.
- Test Facilities, Equipment and Methods