Whole-field holographic measurements of three-dimensional displacement in solid and fluid mechanics
thesisposted on 15.08.2018, 08:11 by Donald H. Barnhart
This thesis reports on the development of two, conceptually different, holographic measurement systems for the study of three-dimensional displacement and velocity fields. The first approach reported in this thesis is an intensity correlation-based holographic velocimetry system that employs a reference-multiplexed, off-axis geometry for determining velocity directions using the cross-correlation technique, and a stereo camera geometry for determining three-dimensional fluid velocity fields. The pulsed-laser recording system produces three-dimensional particle images with resolution, signal-to- noise ratio, accuracy and derived velocity fields that are comparable to high-quality two-dimensional photographic PIV (particle image velocimetry). The high image resolution is accomplished by using low f-number optics, a fringe-stabilized processing chemistry, and a phase conjugate play-back geometry that compensates for aberrations in the imaging system. This holographic velocimetry system is then used to successfully measure the volumetric, three-dimensional velocity field of an air nozzle jet flow. In this experiment, more than five million three-dimensional velocity vectors are successfully identified within a single hologram result. [Continues.]
EPSRC (grant no.: GR/K11147). Royal Society, R.W. Paul Instrument Fund. Rover Group plc.
- Mechanical, Electrical and Manufacturing Engineering