A two-velocity-component directionally sensitive fringe-type rapidly scanning laser Doppler velocimeter (RSLDV) is described, which scans the measurement volume in a direction perpendicular to the optical axis of the transmitting optics and normal to the test flow floor and measures the velocity components perpendicular to the optical axis. Scan rates of up to 300 Hz are possible over 75 mm using a sinusoidal scanning of the position versus time. The RSLDV was designed to permit space-time velocity correlations along a vertical line scan. To illustrate the use of this instrument, some results are presented from measurements performed in the highly turbulent complex three-dimensional flow in fronl of a wing-body junction.
Nomenclature
Fvelocity bias weighting factor N sample size p surface pressure