Experimental Measurement Techniques

What are some of the possible full-field, time-resolved, velocity vector measurements?

The list below are only three of the many possible approaches and variations that are being investigated by researchers in the field. These three have received the most attention and are developed the furthest. They have all been applied to several practical problems. There are other methods that are being developed, some are more complex and have the potential of providing even more detailed information about both the scalar mixing field and the velocity vector field at the same time; however, that is another story for another time. Our plan is to concentrate on the measurement system we have developed (PTV) and is listed first. The current measurement approaches are

1). Measurements using particle tracking velocimetry (PTV) are 3-dimensional, time-resolved, but of low spatial resolution (see publication for this). One example of results is available for the opposed jet reactor. The first link on this page provides details obtained with our low-resolution system. The time resolution was 30 Hz with a spatial resolution of ~256². Our new system operates at higher speeds(60-200 Hz) and higher resolution (~512²).

2). Measurements using particle image velocimetry (PIV) are 2-dimensional, can have adequate time-resolution, and have high spatial resolution. These are commercially available systems today. We have worked on one possible extension to make the system 3-dimensional by scanning the laser sheet and obtaining many 2-dimensional planes.

3). Holographic based approaches are 3-dimensional, currently have low time resolution, and have high spatial resolution. These are very complex and costly systems. They are, however, the next generation beyond the techniques described above.