Common-Path Heterodyne Laser-Induced Thermal Acoustics for Seedless Laser Velocimetry
Abstract
We demonstrate the use of a novel technique for the detection of heterodyne laser-induced thermal acoustics signals, which allows the construction of a highly stable seedless laser velocimeter. A common-path configuration is combined with quadrature detection to provide flow direction, greatly improve robustness to misalignment and vibration, and give reliable velocity measurement at low flow velocities. Comparison with Pitot tube measurements in the freestream of a windtunnel shows root-mean-square errors of 0.67 m/s over the velocity range 0-55 m/s.
- Publication:
-
NASA STI/Recon Technical Report N
- Pub Date:
- December 2001
- Bibcode:
- 2001STIN...0304240H
- Keywords:
-
- Acoustics;
- Heterodyning;
- Laser Doppler Velocimeters;
- Laser Applications;
- Pitot Tubes;
- Quadratures;
- Velocity Measurement;
- Flow Velocity;
- Root-Mean-Square Errors;
- Fluid Mechanics and Thermodynamics