The method used for this experiment is outlined in the following steps:
1. Calibration of the experimental setup. Calibration is necessary to ensure that the images obtained are focussed and the scale factor necessary for processing of the images is obtained. Calibration can be done in a number of ways. The two ways considered during this experiment are: use of a calibration target and real-time analysis of the correlation vectors in the flow field analysed by the computer.
The first way makes use of a calibration target, given in Figure 2.