Particle Image Velocity (PIV) is now a well established, non-intrusive technique for
the two dimensional measurement of fluid velocity from a single plane of interest
within a fluid flow. This thesis presents new work into the application of the double
pulsed PIV technique to highspeed flows. The areas of work can be split into three
The first area of work involved a comprehensive study into data reduction using
autocorrelation. Results from the study allowed the development of an optimisation
method which provides a consistent basis for experimental design. Further work
validated this method by comparing equivalent results from sets of PIV transparencies
processed using a system developed from commercially available image processing
The second area of work involved supersonic flow studies of a de Laval expansion
nozzle. PIV results were recorded from both inside and outside the nozzle. Inside the
nozzle the PIV results resolved a normal shock and allowed comparisons with a 1D
theoretical model, a CFD prediction and Schlieren photographs. Outside the nozzle the
PIV data permitted overexpanded jet shock cell structures to be resolved and
compared to a shock cell model.
The final area of work involved development of an image labelling system for high
speed flows by changing the transfer characteristics of the recording optics between
exposures. A general theory of this technique was developed and a system designed
and tested which can be applied to flows of arbitrarily high speed.
A Doctoral Thesis. Submitted in partial fulfilment of the requirements for the award of Doctor of Philosophy of Loughborough University.