Diagnostics Development

The TF Lab is equipped with a broad suite of laser systems, cameras, synchronization and characterization hardware.  The lab has several data acquisition systems, oscilloscopes, spectrometers, refractometer, etc …

We are striving to conduct multi-physics and multi-scale experiments.  We have thus expanded into laser spectroscopic techniques. We are continuously pushing the limits of existing diagnostics and developing new concepts.  Many of our tools are not commercially available which forces us to develop all aspects of instruments integration and data analysis. This enables us to have a deeper understanding of uncertainties associated with our measurements.   To date our capabilities include:

PIV combined with PLIF profilometry

 

Time-resolved PIV for interface shear

Fiber coupling of PIV lasers

 

Molecular Tagging Velocimetry (MTV) in gases

MTV is a laser spectroscopy technique that was pioneered by NASA.  It relies on the tagging and tracking of molecular probes.  It is therefore particularly adapted to measurements in very high and low speed flows where seeding with particles (like for PIV or LDV) is challenging.

GW MTV system

Our system is transportable and has down a couple of cross-country trips already!  The tunable dye laser has been customized to enable a dual pulse capability for velocimetry. So far we have tested N2O and H2O tracers successfully in a broad range of temperatures and pressures.

MTV in aqueous solutions

MTV below a sheared free surface

We have extended our work on MTV to liquids.  We have been working on two schemes to generate the signals.

Fine pattern generation for MTV

One of the main limitations of MTV has been the ability to generate 2D patterns.  We have been working on a scheme to generate fine 2D patterns.

Tunable Diode Laser Absorption Spectroscopy

PLIF for mass transfer

Doppler Global Velocimetry

 

We are currently working on:

3D profilometry, direct measurements of wall shear stress, void fraction measurements, etc …