Dresden 2009 – scientific programme

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DY: Fachverband Dynamik und Statistische Physik

DY 16: Fluid dynamics I

DY 16.2: Talk

Wednesday, March 25, 2009, 15:00–15:15, ZEU 255

3D flow measurement with Digital Holographic Particle Tracking Velocimetry (DHPTV) — •Tim Homeyer and Gerd Gülker — Carl von Ossietzky University Oldenburg - Institute of Physics - Hydrodynamics and Windenergy, Germany

The two-dimensional flow measurement technique PIV (Particle Image Velocimetry) is a standard method to investigate air or fluid flows. After seeding the fluid with small light scattering particles, a laser light sheet is created, and two fast consecutive images of the illuminated field are recorded. These images are correlated in a computer and resulting in a two-dimensional vector field of the flow velocity.

This technique is extended to the third dimension using holography (Holographic PIV). By recording a volume in a hologram and subsequent reconstruction, the whole three-dimensional particle field of the flow is captured.

For small volumes, one can also record the holograms with a digital camera, instead of using film material. This has the advantage that recording and reconstruction is directly performed in the computer and no chemical development and additional digitizing is needed. Due to noise the number of particles has to be reduced. That is why each particle is identified, validated and tracked through the volume (Particle Tracking Velocimetry) instead of performing a 3D correlation (PIV).

The goals of this diploma thesis are to design a DHPTV system to record small three-dimensional flows in a wind tunnel and in Rayleigh-Bénard-Cells and to compare different types of particle validation methods.