1. where λLis the laser wavelength, a^ is a unit vector in the direction of observation, l^ is a unitvector in the direction of the laser, and Vr is the velocity vector of the fluid element being measured. The vectors are shown in Figure 7. The vector l a ^ ^ - represents the direction of the measured velocity component for the Doppler measurements presented here. It can be shown that fromthis geometrythe magnitude of the vector l a ^ ^ - isequalto 0.7654. Substituting this value into Eq. (1), and using 532 nm for the laser wavelength, the Doppler shift is computed to be -1.33 MHz per m/s. Figure 6. Configuration usedPDVexperiments in aturbojet engine
2. (m/s) 45K 100 -133 -115 86 55K 128 -170 -160 120 65K 160 -213 -230 172 74K 190 -253 -310 233 C. Doppler Shifts Measured in the Engine Exhaust
3. This work was supported by the Naval Air Warfare Center, Aircraft Division, under contract N68335-11-C0435.