Velocity measurements in a separating turbulent boundary using sampling spectrum analysis
Abstract
A mobile backscattering laser anemometer utilizing dual Bragg cells has been developed to measure the magnitude and direction of the flow in a separating turbulent boundary layer. Signal processing was achieved by using a spectrum analyzer capable of a 8 KHz sweep frequency interfaced with signal sampling electronics. This relatively inexpensive signal processing method is particularly useful for high dropout flows and high signal frequencies produced by frequency shifting one incident beam. The greater the sweep frequency, the larger the attenuation of the spectrum analyzer output. Thus at only large signaltonoise ratios can the fastest sweep frequencies be used. Experimental results obtained to date with this system are discussed.
 Publication:

2nd International Workshop on Laser Velocimetry, Volume 2
 Pub Date:
 1974
 Bibcode:
 1974lave....2...15S
 Keywords:

 Anemometers;
 Boundary Layer Separation;
 Laser Applications;
 Signal Processing;
 Spectrum Analysis;
 Turbulent Boundary Layer;
 Backscattering;
 Bragg Cells;
 Data Sampling;
 Signal To Noise Ratios;
 Smoke;
 Velocity Distribution;
 Velocity Measurement;
 Wind Tunnels;
 Instrumentation and Photography