3D Particle Tracking Velocimetry (3D PTV)
3D-PTV allows characterizing 3D flow field in a Lagrangian frame of reference. The technique has been developed and optimized in collaboration with OpenPTV. The apparatus uses a view splitter which produces four different views of an interrogation volume, which are captured with a high-resolution and highly-sensitive camera. We are using 3D-PTV in fundamental Fluid Mechanic applications such as turbulent jets, flow around structures and biological species. Figures 1-3 show an example of 3D-PTV setup in the RE-TE-G Jet flume and Figure 4 shows a set of particle trajectories in the intermediate region of a circular jet flow.
Video 1: The JoVE video article on turbulent jets (Kim J-T., Kim D., Liberzon A., and Chamorro L.P. (2015) J Visual Exp.)
Figure 1: 3D-PTV setup in the jet flume
Figure 2: Custom-made calibration plate (Left); views by the image splitter (middle); and various nozzles geometries (right).
Figure 3: Experiments on a jet flow and details of the flow.
Figure 4: a) Sample trajectories; b) mean axial velocity in 3D grid for the circular jet.
The motion and induced flow in the near wake of a small jellyfish, Aurelia aurita, were characterized and quantified from a Lagrangian frame of reference using 3D Particle Tracking Velocimetry (3D-PTV). Figure 5 shows the 3D-PTV setup in the RE-TE-G jellyfish tank, Figure 6 shows a set of particle trajectories and Figure 7 shows 3D velocity grid with out of plane vortices.
Figure 5: a) Basic schematic of the experimental setup; b)stereoscopic four-view image.
Figure 6: Sample flow trajectories colored based on a) axial and b) radial velocities.
Figure 7: a) 3D Eulerian velocity field with in-plane vorticity field; b) in-plane vorticity with superimposed velocity field.
Our research group aims at providing fundamental insights on the role of turbulence in basic and applied problems of high interest, which can be divided in the following sub-areas:
i) structure of the boundary layer over complex topographies;
ii) wind & hydrokinetic energy technologies,
iii) scalar transport over urban and natural environments,
iv) flow-structure interaction; and
v) instrumentation for turbulence measurements.
We have developed a comprehensive research on these topics that are going to be sustained and expanded in the future. Our versatile experimental approach combines a set of state-of-the-art experimental techniques, including particle image velocimetry (PIV), computer vision, and our recently developed 3D particle tracking velocimetry (PTV). This framework allows us to study fluid dynamics from Eulerian and Lagrangian frame of references