Full text loading...
The experimental setup is shown (a) along with a detailed look at the geometry of the projectile and the arrangement of sensing probes (b). The distance between each probe and the projectile (working distance) is indicated “WD” (b). The projectile's dimensions are to scale, and it measured 16 mm tall and 47 mm long.
Normal Probe measurements show low-frequency amplitude fluctuations (b) not present in the case of purely axial motion (a).
Velocity along the beam is shown for the bore probe (a) and angled probe (b). Angled probe axial velocities are cos(63°) times those measured by the bore probe (consistent with Fig. 1(b) ).
The autocorrelation's decay (i.e., the coherence time) is indicative of the projectile's transverse speed.
Transverse speed is calculated from speckle dynamics for the normal probe (a), (c), (e) and for the angled probe (b), (d), (f) and is compared with the velocity measured by the bore probe. The horizontal axis indicates the beam position on the target surface. Note, that the scales of the vertical axes vary from plot to plot and that the speckle analysis is clearly tracking relative changes in velocity from trial to trial. The systematic bias in (a), (c), and (e) will be the subject of further research.
Article metrics loading...